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Groups > comp.arch.embedded > #13136 > unrolled thread
| Started by | Joerg <invalid@invalid.invalid> |
|---|---|
| First post | 2013-08-19 13:14 -0700 |
| Last post | 2013-09-02 22:27 +0200 |
| Articles | 20 on this page of 146 — 17 participants |
Back to article view | Back to comp.arch.embedded
AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-08-19 13:14 -0700
Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-08-20 20:16 +0100
Re: AREF bypass capacitance on ATMega2560? Vladimir Vassilevsky <nospam@nowhere.com> - 2013-08-21 14:47 -0500
Re: AREF bypass capacitance on ATMega2560? Jim Stewart <jstewart@jkmicro.com> - 2013-08-21 13:18 -0700
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-08-21 16:38 -0700
Re: AREF bypass capacitance on ATMega2560? "Tim Williams" <tmoranwms@charter.net> - 2013-08-21 21:30 -0500
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-08-22 10:51 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-06 16:26 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-06 13:33 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-06 17:12 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-06 16:10 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-06 23:59 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 08:10 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:03 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 10:59 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 14:54 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 12:39 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 16:44 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 14:48 -0700
Re: AREF bypass capacitance on ATMega2560? "Tim Williams" <tmoranwms@charter.net> - 2013-09-07 17:10 -0500
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 15:34 -0700
Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-08 00:57 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 16:56 -0700
Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-09 17:07 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 10:19 -0700
Re: AREF bypass capacitance on ATMega2560? Paul <paul@pcserviceselectronics.co.uk> - 2013-09-09 20:27 +0100
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 12:55 -0700
Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-11 09:44 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 07:27 -0700
Re: AREF bypass capacitance on ATMega2560? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2013-09-13 12:42 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-14 11:56 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 19:38 -0400
Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 17:39 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 23:20 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 07:41 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-07 11:17 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:23 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:19 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 14:03 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 19:42 -0400
Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-08 17:18 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-09 13:13 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 20:21 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-10 23:42 -0400
Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-07 09:24 +0100
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 10:00 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-07 11:32 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:35 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:30 -0400
Re: AREF bypass capacitance on ATMega2560? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2013-09-09 09:56 -0400
Re: AREF bypass capacitance on ATMega2560? Robert Wessel <robertwessel2@yahoo.com> - 2013-09-12 11:50 -0500
Re: AREF bypass capacitance on ATMega2560? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2013-09-12 15:06 -0400
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-12 14:57 +0200
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 00:21 -0400
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 14:08 +0200
Re: AREF bypass capacitance on ATMega2560? Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-09-13 15:15 +0100
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 11:46 -0400
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 18:43 +0200
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 19:14 +0200
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 15:26 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 15:24 -0400
Re: AREF bypass capacitance on ATMega2560? David Brown <david.brown@removethis.hesbynett.no> - 2013-09-13 20:22 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 09:32 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 13:44 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 12:46 -0700
Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 13:33 -0700
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 13:46 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 17:05 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 15:23 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 19:02 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 16:45 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 23:16 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 08:05 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 14:27 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 12:56 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:07 -0400
Re: AREF bypass capacitance on ATMega2560? Tom Gardner <spamjunk@blueyonder.co.uk> - 2013-09-11 10:05 +0100
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 07:49 -0700
Re: AREF bypass capacitance on ATMega2560? Paul <paul@pcserviceselectronics.co.uk> - 2013-09-11 16:54 +0100
Re: AREF bypass capacitance on ATMega2560? "Tim Williams" <tmoranwms@charter.net> - 2013-09-11 11:25 -0500
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 09:49 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:40 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:38 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 09:34 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 14:29 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 13:01 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 16:22 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:09 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 16:15 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 14:20 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 18:15 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 15:57 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 19:46 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-08 17:15 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 20:20 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 07:17 -0700
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 12:17 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-09 19:30 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-09 16:38 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-10 14:02 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:41 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-11 00:04 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-11 07:53 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-11 21:50 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 09:58 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-12 18:54 -0400
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-12 16:17 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 10:03 -0700
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-12 19:24 +0200
Re: AREF bypass capacitance on ATMega2560? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-09-12 20:38 +0300
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 11:23 -0700
Re: AREF bypass capacitance on ATMega2560? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-09-12 22:36 +0300
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 12:41 -0700
Re: AREF bypass capacitance on ATMega2560? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2013-09-12 23:08 +0300
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 11:19 -0700
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-12 18:59 -0400
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 13:00 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-14 12:05 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-12 16:03 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-12 14:42 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-13 00:24 -0400
Re: AREF bypass capacitance on ATMega2560? Piotr Wyderski <peter.pan@neverland.mil> - 2013-09-13 14:27 +0200
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-14 12:07 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-15 02:26 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-15 09:51 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-13 20:06 -0400
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 16:50 -0400
Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 14:33 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 19:07 -0400
Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-07 16:31 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 23:38 -0400
Re: AREF bypass capacitance on ATMega2560? Paul Rubin <no.email@nospam.invalid> - 2013-09-08 20:19 -0700
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:36 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:46 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 11:36 -0400
Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-08 09:04 +0100
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 13:42 -0400
Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-08 19:04 +0100
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-08 07:29 -0400
Re: AREF bypass capacitance on ATMega2560? John Devereux <john@devereux.me.uk> - 2013-09-09 08:56 +0100
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-10 23:54 -0400
Re: AREF bypass capacitance on ATMega2560? krw@attt.bizz - 2013-09-08 16:24 -0400
Re: AREF bypass capacitance on ATMega2560? Ulf Samuelsson <ulf_samuelsson@invalid.telia.com> - 2013-09-07 20:11 +0200
Re: AREF bypass capacitance on ATMega2560? rickman <gnuarm@gmail.com> - 2013-09-07 15:06 -0400
Re: AREF bypass capacitance on ATMega2560? Joerg <invalid@invalid.invalid> - 2013-09-07 12:54 -0700
Re: AREF bypass capacitance on ATMega2560? Ulf Samuelsson <ulf_samuelsson@invalid.telia.com> - 2013-09-02 22:27 +0200
Page 7 of 8 — ← Prev page 1 2 3 4 5 6 [7] 8 Next page →
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-13 00:24 -0400 |
| Message-ID | <l0u3qu$h9n$2@dont-email.me> |
| In reply to | #13519 |
On 9/12/2013 5:42 PM, Joerg wrote: > rickman wrote: >> On 9/12/2013 1:03 PM, Joerg wrote: >>> Piotr Wyderski wrote: >>>> Joerg wrote: >>>> >>>>> Question: What do you do with an FPGA in a radio? >>>> >>>> As a matter of fact, it is one of the best places to use an FPGA. :-) >>>> SDR with FPGA reconfiguration capabilities is the ideal solution. >>>> Not for a regular FM noisemaker, though... >>>> >>>> Best regards, Piotr >>>> >>>> *) It was exactly the only time in my life when I used an FPGA. >>>> + a 14-bit@65MHz Analog Devices ADC + 104 MHz DAC. >>>> >>> >>> It's going to be a tough sell for a radio. Even if they found one for $3 >>> that's too much and they also can't stomach the 10sec to download the >>> compiled data in production. >> >> You really have no interest in learning anything about FPGAs that has >> happened in the last 10 or 15 years do you? >> > > Oh, I do. I just reviewed a design that has some rather fat ones in > there and it would hardly have been possible to do this without FPGA. > However, there are circuits where FPGAs are a perfect fit and others > where they just aren't. In ordinary radios they usually aren't. > >> >>> Everything has to fit into the $149.95 sale price at the auto parts >>> place, with fat profit margins for everyone and their middlemen, >>> speakers, wires, neon-colored huge window sticker, a discount coupon for >>> installation, free coffee and free waffles :-) >> >> You two are talking about totally different radios. >> > > The last few posts were about car radios, because the topic was > electronics and temperature exposure in cars. When Piotr started talking about SDR he wasn't talking about car radios anymore. -- Rick
[toc] | [prev] | [next] | [standalone]
| From | Piotr Wyderski <peter.pan@neverland.mil> |
|---|---|
| Date | 2013-09-13 14:27 +0200 |
| Message-ID | <l0v0ce$8pt$1@node2.news.atman.pl> |
| In reply to | #13528 |
rickman wrote: > When Piotr started talking about SDR he wasn't talking > about car radios anymore. Yes, something more like this class stuff: https://en.wikipedia.org/wiki/Joint_Tactical_Radio_System Best regards, Piotr
[toc] | [prev] | [next] | [standalone]
| From | Joerg <invalid@invalid.invalid> |
|---|---|
| Date | 2013-09-14 12:07 -0700 |
| Message-ID | <b9jqg2FskevU2@mid.individual.net> |
| In reply to | #13538 |
Piotr Wyderski wrote: > rickman wrote: > >> When Piotr started talking about SDR he wasn't talking >> about car radios anymore. > > Yes, something more like this class stuff: > > https://en.wikipedia.org/wiki/Joint_Tactical_Radio_System > That's a whole different ballgame. When it comes to spread spectrum, high frequency agility and similar traits it has to be SDR. But for those guys cost (and to some extent power consumption) is not a concern. Because the taxpayer foots the bill. -- Regards, Joerg http://www.analogconsultants.com/
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-15 02:26 -0400 |
| Message-ID | <l13jvl$m7g$1@dont-email.me> |
| In reply to | #13584 |
On 9/14/2013 3:07 PM, Joerg wrote: > Piotr Wyderski wrote: >> rickman wrote: >> >>> When Piotr started talking about SDR he wasn't talking >>> about car radios anymore. >> >> Yes, something more like this class stuff: >> >> https://en.wikipedia.org/wiki/Joint_Tactical_Radio_System >> > > That's a whole different ballgame. When it comes to spread spectrum, > high frequency agility and similar traits it has to be SDR. But for > those guys cost (and to some extent power consumption) is not a concern. > Because the taxpayer foots the bill. Funny that you mention that cost doesn't matter because the "taxpayer" is footing the bill. I worked at a company making exactly those radios and the engineering discussions would be about the safety of the soldiers rather than "who cares, the tax payer is paying for it". The very best performance is demanded because there are many times when the mission depends on it including lives. But you are right in that cost is not a primary factor. There is waste. But mostly that comes from misdirected government influences. In the case of these radios the government wanted to "save money" by reusing designs in multiple platforms. But that usually meant making the design more expensive to perform a wider mission with more capabilities. In the end it was a massive effort that may have saved some money or may well have cost more than it saved. -- Rick
[toc] | [prev] | [next] | [standalone]
| From | krw@attt.bizz |
|---|---|
| Date | 2013-09-15 09:51 -0400 |
| Message-ID | <fneb39p4c69au6j12ieg9qs21r1i542btl@4ax.com> |
| In reply to | #13590 |
On Sun, 15 Sep 2013 02:26:44 -0400, rickman <gnuarm@gmail.com> wrote: >On 9/14/2013 3:07 PM, Joerg wrote: >> Piotr Wyderski wrote: >>> rickman wrote: >>> >>>> When Piotr started talking about SDR he wasn't talking >>>> about car radios anymore. >>> >>> Yes, something more like this class stuff: >>> >>> https://en.wikipedia.org/wiki/Joint_Tactical_Radio_System >>> >> >> That's a whole different ballgame. When it comes to spread spectrum, >> high frequency agility and similar traits it has to be SDR. But for >> those guys cost (and to some extent power consumption) is not a concern. >> Because the taxpayer foots the bill. > >Funny that you mention that cost doesn't matter because the "taxpayer" >is footing the bill. I worked at a company making exactly those radios >and the engineering discussions would be about the safety of the >soldiers rather than "who cares, the tax payer is paying for it". The >very best performance is demanded because there are many times when the >mission depends on it including lives. But you are right in that cost >is not a primary factor. > >There is waste. But mostly that comes from misdirected government >influences. In the case of these radios the government wanted to "save >money" by reusing designs in multiple platforms. But that usually meant >making the design more expensive to perform a wider mission with more >capabilities. In the end it was a massive effort that may have saved >some money or may well have cost more than it saved. Nonsense. There is waste from top to bottom, some incompetence, some because cost just isn't an important parameter, and yes, some because the whole idea is just dumb. Your admiration for the government's forward thinking is cute, though.
[toc] | [prev] | [next] | [standalone]
| From | krw@attt.bizz |
|---|---|
| Date | 2013-09-13 20:06 -0400 |
| Message-ID | <lv9739prot3loabrm5ta5rst5iiqqutbql@4ax.com> |
| In reply to | #13528 |
On Fri, 13 Sep 2013 00:24:44 -0400, rickman <gnuarm@gmail.com> wrote: >On 9/12/2013 5:42 PM, Joerg wrote: >> rickman wrote: >>> On 9/12/2013 1:03 PM, Joerg wrote: >>>> Piotr Wyderski wrote: >>>>> Joerg wrote: >>>>> >>>>>> Question: What do you do with an FPGA in a radio? >>>>> >>>>> As a matter of fact, it is one of the best places to use an FPGA. :-) >>>>> SDR with FPGA reconfiguration capabilities is the ideal solution. >>>>> Not for a regular FM noisemaker, though... >>>>> >>>>> Best regards, Piotr >>>>> >>>>> *) It was exactly the only time in my life when I used an FPGA. >>>>> + a 14-bit@65MHz Analog Devices ADC + 104 MHz DAC. >>>>> >>>> >>>> It's going to be a tough sell for a radio. Even if they found one for $3 >>>> that's too much and they also can't stomach the 10sec to download the >>>> compiled data in production. >>> >>> You really have no interest in learning anything about FPGAs that has >>> happened in the last 10 or 15 years do you? >>> >> >> Oh, I do. I just reviewed a design that has some rather fat ones in >> there and it would hardly have been possible to do this without FPGA. >> However, there are circuits where FPGAs are a perfect fit and others >> where they just aren't. In ordinary radios they usually aren't. >> >>> >>>> Everything has to fit into the $149.95 sale price at the auto parts >>>> place, with fat profit margins for everyone and their middlemen, >>>> speakers, wires, neon-colored huge window sticker, a discount coupon for >>>> installation, free coffee and free waffles :-) >>> >>> You two are talking about totally different radios. >>> >> >> The last few posts were about car radios, because the topic was >> electronics and temperature exposure in cars. > >When Piotr started talking about SDR he wasn't talking about car radios >anymore. He may not have been but (parts of) car radios are SDR.
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-07 16:50 -0400 |
| Message-ID | <l0g3jo$bau$1@dont-email.me> |
| In reply to | #13358 |
On 9/7/2013 4:33 PM, Paul Rubin wrote: > Joerg<invalid@invalid.invalid> writes: >> I don't see how the equivalent of a TMS320 or a big MSP430 could fit >> into one of these small Lattice devices. > > I had thought the parts of those processors that would bloat up badly > (instruction decode etc.) are pretty simple so the overall effect of the > bloat is ok in the scheme of things. The parts doing the most work > (memory, arithmetic) are done in the FPGA hardware (RAM and DSP blocks, > adders connected to the LUT's somehow) as efficiently as on the MCU's. > > I do think softcores seem like a silly idea a lot of the time, and am > looking forward to more low end FPGA's with MCU blocks. How about an MCU array instead? http://www.greenarraychips.com/ BTW, considering a softcore "silly" is not a useful engineering analysis. Softcores can save money and/or time in a project. But then people often have biases and aren't willing to look at things from a different perspective. Bernd Paysan rolled his own small processor design for an ASIC and was able to save time *and* money in development as well as silicon cost over using a canned core in a custom ASIC design. Dig around a bit and find the B16 for more details. Or he would be happy to relate the fiasco of the whole project (it started with an 8051 core). -- Rick
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| From | Paul Rubin <no.email@nospam.invalid> |
|---|---|
| Date | 2013-09-07 14:33 -0700 |
| Message-ID | <7xy578mi4q.fsf@ruckus.brouhaha.com> |
| In reply to | #13361 |
rickman <gnuarm@gmail.com> writes: > How about an MCU array instead? http://www.greenarraychips.com/ Yes, we've had many discussions about that part ;-). > considering a softcore "silly" is not a useful engineering analysis. The engineering analysis is implied: it takes far more silicon to implement a microprocessor in LUTs than directly in silicon, plus you lose a lot of speed because of all the additional layers and lookups. > Bernd Paysan rolled his own small processor design for an ASIC Yes, the ASIC bypassed the relative inefficiency of doing the same thing in FPGA's. It would be cool to have some tiny processors like that available as hard cells on small FPGA's.
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-07 19:07 -0400 |
| Message-ID | <l0gbj8$no5$1@dont-email.me> |
| In reply to | #13363 |
On 9/7/2013 5:33 PM, Paul Rubin wrote: > rickman<gnuarm@gmail.com> writes: >> How about an MCU array instead? http://www.greenarraychips.com/ > > Yes, we've had many discussions about that part ;-). > >> considering a softcore "silly" is not a useful engineering analysis. > > The engineering analysis is implied: it takes far more silicon to > implement a microprocessor in LUTs than directly in silicon, plus you > lose a lot of speed because of all the additional layers and lookups. That is a pointless comparison. I have never once opened up a chip to see how much silicon it used. I compare the things I can see from the outside, cost, power consumption, etc... You can infer anything you wish. The proof of the pudding is in the eating. This exactly the type of bias I'd like to overcome. >> Bernd Paysan rolled his own small processor design for an ASIC > > Yes, the ASIC bypassed the relative inefficiency of doing the same thing > in FPGA's. It would be cool to have some tiny processors like that > available as hard cells on small FPGA's. Ok, but your "efficiency" rating is not any of real value in a design. Stop limiting yourself by pointless metrics. If you like the idea of a lot of processors on a chip, then design one on an FPGA and see how it works. Do you see what I'm trying to say? -- Rick
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| From | Paul Rubin <no.email@nospam.invalid> |
|---|---|
| Date | 2013-09-07 16:31 -0700 |
| Message-ID | <7x1u50yzsi.fsf@ruckus.brouhaha.com> |
| In reply to | #13370 |
rickman <gnuarm@gmail.com> writes: > That is a pointless comparison. I have never once opened up a chip to > see how much silicon it used. I compare the things I can see from the > outside, cost, power consumption, etc... Yes, and those are quite closely dependent on the amount of silicon used. > You can infer anything you wish. The proof of the pudding is in the > eating. OK. That GA144 you mentioned has 144 cpu nodes made in a rather old process technology (0.18 micron, I guess 1990's vintage). They still manage to run the thing at 700+ Mhz, keep power consumption to around 0.5W with all cpu's running full speed, and sell it for $20 in small quantity. Can you do anyting like that with an FPGA? What will it cost? How much power will it use? I'll accept the b16 as a comparable processor to a GA144 node. Bernd's paper mentions the b16 ran at 25 MHz in a Flex10K30E, a 30-to-1 slowdown, power consumption not mentioned. But I don't know how the underlying silicon processes compare.
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-07 23:38 -0400 |
| Message-ID | <l0grgp$n7r$1@dont-email.me> |
| In reply to | #13371 |
On 9/7/2013 7:31 PM, Paul Rubin wrote: > rickman<gnuarm@gmail.com> writes: >> That is a pointless comparison. I have never once opened up a chip to >> see how much silicon it used. I compare the things I can see from the >> outside, cost, power consumption, etc... > > Yes, and those are quite closely dependent on the amount of silicon used. Nonsense. If you want to know how much water has collected in the basement because of a burst pipe, do you call the water authority to read the meter? No, you put a stick in the water and measure it. If you want to know a parameter, then measure that parameter, don't infer it from something only vaguely related. You have a bias against soft cores because you want to analyze them in a meaningless way. How about analyzing them in the terms that you care about? >> You can infer anything you wish. The proof of the pudding is in the >> eating. > > OK. That GA144 you mentioned has 144 cpu nodes made in a rather old > process technology (0.18 micron, I guess 1990's vintage). They still > manage to run the thing at 700+ Mhz, keep power consumption to around > 0.5W with all cpu's running full speed, and sell it for $20 in small > quantity. Can you do anyting like that with an FPGA? Like what exactly? Do 700 MIPS, of course you can. An FPGA can be configured to run your algorithm more exactly than any processor and so it can get very low power. BTW, you know the GA144 doesn't do 700 MIPS either. It is less than half that with most code. The GA144 isn't 0.5 Watts either, it is close to 1 Watt with all nodes running. It also doesn't cost $20 to use because it requires a *ton* of support devices, boot prom, RAM, clock, 1.8 volt to *everything else* voltage translation, etc... I actually considered using it in my board redesign. I might have to add a RAM chip to it, but all the clocks are external to the board anyway and there is already a low voltage power supply. So the main issue is the voltage translation which is partly dealt with currently since the current FPGA had to be buffered to some of the I/O for 5 volt logic. So the GA144 might do ok in that design. But then there is the reason I am doing a redesign... the FPGA is EOL. I don't have much confidence GA will be around in 10 years. Do you know of one major design win they have had? > What will it > cost? You haven't told me what the design requirements are... how can I possibly give you a price? > How much power will it use? How long is a piece of string? > I'll accept the b16 as a comparable > processor to a GA144 node. Bernd's paper mentions the b16 ran at 25 MHz > in a Flex10K30E, a 30-to-1 slowdown, power consumption not mentioned. > But I don't know how the underlying silicon processes compare. You are trying to compare apples to horses. No, you can't use an FPGA to implement some existing processor and improve on cost, power or any other parameter. I never said you could. That would be like using a kitchen knife as a razor. It won't work so well and has little value. But if you have an application - it may well be easier to implement in an FPGA than in a GA144... in fact, I can almost guarantee that! -- Rick
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| From | Paul Rubin <no.email@nospam.invalid> |
|---|---|
| Date | 2013-09-08 20:19 -0700 |
| Message-ID | <7xzjrmfzqk.fsf@ruckus.brouhaha.com> |
| In reply to | #13378 |
rickman <gnuarm@gmail.com> writes: > You have a bias against soft cores because you want to analyze them in > a meaningless way. How about analyzing them in the terms that you > care about? Nothing I have seen indicates any problem with my analysis, which is grounded in basic knowledge of how these circuits work. FPGA's don't run on magic pixie dust. They have the same gates, memory cells, etc. that other chips do. If you've got some evidence saying otherwise, I think it's on you to put up the numbers.q > The GA144 isn't 0.5 Watts either, it is close to 1 Watt with all nodes > running. Still not too bad. > I don't have much confidence GA will be around in 10 years. Do you > know of one major design win they have had? I have doubts about GA too, but it's irrelevant. They did something with a quite low tech ASIC design and fab process, which doesn't appear to be possible with FPGA's without much more advanced fab tech. > No, you can't use an FPGA to implement some existing processor and > improve on cost, power or any other parameter. I never said you > could. Why are you going on about softcores then? A big attraction of softcores is to use code and compilers that you already have, instead of building your application from scratch in Verilog. That generally means implementing an existing processor. How else are you going to run that code? > But if you have an application - it may well be easier to implement in > an FPGA than in a GA144... The comparison was simply between hard and soft processors of similar programmability to see how they did in terms of cost and speed.
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-10 23:36 -0400 |
| Message-ID | <l0oocn$vc1$1@dont-email.me> |
| In reply to | #13411 |
On 9/8/2013 11:19 PM, Paul Rubin wrote: > rickman<gnuarm@gmail.com> writes: >> You have a bias against soft cores because you want to analyze them in >> a meaningless way. How about analyzing them in the terms that you >> care about? > > Nothing I have seen indicates any problem with my analysis, which is > grounded in basic knowledge of how these circuits work. FPGA's don't > run on magic pixie dust. They have the same gates, memory cells, > etc. that other chips do. If you've got some evidence saying otherwise, > I think it's on you to put up the numbers.q Paul, it is silly to guesstimate cost, etc from a parameter distantly related when you can just measure the... well, *cost*. >> The GA144 isn't 0.5 Watts either, it is close to 1 Watt with all nodes >> running. > > Still not too bad. Really? That's the same ballpark as the high end ARMs powering phone and tablets. The difference is the GA144 can't do as much. Lots of paper MIPs, but a pointless parameter in this case. >> I don't have much confidence GA will be around in 10 years. Do you >> know of one major design win they have had? > > I have doubts about GA too, but it's irrelevant. They did something > with a quite low tech ASIC design and fab process, which doesn't appear > to be possible with FPGA's without much more advanced fab tech. They did something that has no real value that I can tell. How is that irrelevant? That is actually the *point*. Who cares if an FPGA can do something of no value... actually I'm sure they can. But why bother to figure it out? >> No, you can't use an FPGA to implement some existing processor and >> improve on cost, power or any other parameter. I never said you >> could. > > Why are you going on about softcores then? A big attraction of > softcores is to use code and compilers that you already have, instead of > building your application from scratch in Verilog. That generally means > implementing an existing processor. How else are you going to run that > code? I never said any of that. If you have a huge library of existing code running on ARM processors then maybe you should stick with what you know. Besides, it is illegal to implement an ARM in a softcore. Ask ARM, they will be happy to point out all the patents you would be violating. >> But if you have an application - it may well be easier to implement in >> an FPGA than in a GA144... > > The comparison was simply between hard and soft processors of similar > programmability to see how they did in terms of cost and speed. It is not a comparison I care about. Your measure of cost is rather bogus if you base it on silicon area. Your measure of performance of the GA144 is totally bogus. Who cares about MIPS of a processor that uses an instruction set unlike nearly any other? Lets measure the GA144 in terms of some useful app it actually runs. Maybe because we don't know of any...? Ya know, I'm actually a proponent of the GA144. But in trying to use the device, I discovered how limited its applications really are. I used to argue that you just needed to learn how to divide your app into appropriate sized pieces for the many, limited processors on the chip. But there is a lot more to an MCU than MIPS. The GA144 was never designed to be a very useful MCU, at least in the professional world. I think it makes a good hobby chip. Now to swing back the other way, my cash cow board uses an FPGA which is going EOL. I can't find a replacement FPGA that I can use with 6 mil space and trace and 10 mil vias on my PCB. Everything else I find either is also very long in the tooth or is too little logic or comes in a package that requires 4/4 design rules (or smaller). But the GA144 might just do the job. One limitation is the tiny memory. A delay buffer is needed that might be too much for the on chip RAM. But I don't know how I could ever trust that GA will be around for the next year much less the next 10. -- Rick
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| From | krw@attt.bizz |
|---|---|
| Date | 2013-09-08 11:46 -0400 |
| Message-ID | <rn6p291j47spjod8i78mjfd7nlrv9rsupq@4ax.com> |
| In reply to | #13363 |
On Sat, 07 Sep 2013 14:33:41 -0700, Paul Rubin <no.email@nospam.invalid> wrote: >rickman <gnuarm@gmail.com> writes: >> How about an MCU array instead? http://www.greenarraychips.com/ > >Yes, we've had many discussions about that part ;-). > >> considering a softcore "silly" is not a useful engineering analysis. > >The engineering analysis is implied: it takes far more silicon to >implement a microprocessor in LUTs than directly in silicon, plus you >lose a lot of speed because of all the additional layers and lookups. Yes, and add the "markup" for *being* an FPGA (production quantities). >> Bernd Paysan rolled his own small processor design for an ASIC Even more silly. I've done silly things like this but only because of stupid management edicts (*NOT* based on any engineering analysis). >Yes, the ASIC bypassed the relative inefficiency of doing the same thing >in FPGA's. It would be cool to have some tiny processors like that >available as hard cells on small FPGA's. Yes, but it would still be quite expensive, compared to a similar (external) uC, including the I/O.
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| From | krw@attt.bizz |
|---|---|
| Date | 2013-09-08 11:36 -0400 |
| Message-ID | <366p29ldotr0m888nile2so7kkt0m2nvj7@4ax.com> |
| In reply to | #13356 |
On Sat, 07 Sep 2013 12:46:59 -0700, Joerg <invalid@invalid.invalid> wrote: >I don't see how the equivalent of a TMS320 or a big MSP430 could fit >into one of these small Lattice devices. BTW, watch the TMS320 5000series parts. The DMA is seriously broken if you're using the BSP (I2S/TDM interfaces). The McBSP sucks, too, but that's a different issue. Last I knew they had no intention of fixing I2S/TDM DMA, either.
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| From | John Devereux <john@devereux.me.uk> |
|---|---|
| Date | 2013-09-08 09:04 +0100 |
| Message-ID | <87ppsjzql6.fsf@devereux.me.uk> |
| In reply to | #13342 |
rickman <gnuarm@gmail.com> writes: > On 9/7/2013 4:24 AM, John Devereux wrote: >> rickman<gnuarm@gmail.com> writes: >> >>> If your FPGA designs are expensive or power hungry, then you are doing >>> things you can't do in an MCU or you are not using FPGAs properly. >>> They don't need to use any more power than an MCU and in many cases >>> less. They certainly don't need to be significantly more expensive >>> unless you consider every dollar in your designs. At the very low end >>> MCUs can be under $1 and still have reasonable performance. For $1 >>> you can't get much in the way of programmable logic. For $3 however, >>> you can get a chip large enough for a CPU (with math) and room for >>> your special logic. >> >> I've never used an FPGA, microcontrollers have increased in speed faster >> than my needs so far. So I can usually bitbang everything or use a >> peripheral. I used PLDs for glue logic back in the day but that's it. Oh >> and I bought a small xilinx dev kit which I got to make a led flash then >> put in a drawer for 15 years. > > So your use of MCUs is based on inertia? Partly I suppose. Or I could say that my projects so far all require a microcontroller anyway, and it seemed likely that a separate FPGA was always going to be more expensive than, say, choosing a faster CPU. A STM32F4 can bitbang a PIO at 84MHz. (It can't do anything else then, but still...) >> But could you give an example of your $3 one? Or a favorite? > > A startup company called Silicon Blue came out with a line of FPGAs > targeted to the high volume, low power market that exists for portable > devices. They were preparing their second device family and were > bought by Lattice Semi. The first family was dropped and the second > family is the iCE40 (for 40 nm). They are very low power although > smallish. The largest one has 8 kLUTs, the smallest 384 LUTs. > > Last winter I was looking at designing a very low power radio > controlled clock to run in one of these. They were still playing a > shell game with the devices in the lineup and the 640 LUT part I > wanted to use was dropped... :( The only real problem I have with > these devices is the packaging. Because of the target market the > packages are mostly fine pitch BGAs. Great if you are making a cell > phone, not so great if you are designing other equipment. > > You can get the 1 kLUT parts for under $3 and possibly the 4 kLUT > parts. It has been a while since I got a quote. The 1 kLUT part is > big enough for a soft core MCU plus some custom logic. OK, thanks, will check them out. > BTW, with MCUs Digikey will give you a realistic price quote. In the > FPGA world the distis never give you a good price unless you ask for a > quantity quote. I have gotten prices quoted to me that were half the > list price. FPGA companies play a different marketing game and have a > lot of room to negotiate in order to buy a socket. -- John Devereux
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-08 13:42 -0400 |
| Message-ID | <l0icti$1vc$1@dont-email.me> |
| In reply to | #13379 |
On 9/8/2013 4:04 AM, John Devereux wrote: > rickman<gnuarm@gmail.com> writes: > >> On 9/7/2013 4:24 AM, John Devereux wrote: >>> rickman<gnuarm@gmail.com> writes: >>> >>>> If your FPGA designs are expensive or power hungry, then you are doing >>>> things you can't do in an MCU or you are not using FPGAs properly. >>>> They don't need to use any more power than an MCU and in many cases >>>> less. They certainly don't need to be significantly more expensive >>>> unless you consider every dollar in your designs. At the very low end >>>> MCUs can be under $1 and still have reasonable performance. For $1 >>>> you can't get much in the way of programmable logic. For $3 however, >>>> you can get a chip large enough for a CPU (with math) and room for >>>> your special logic. >>> >>> I've never used an FPGA, microcontrollers have increased in speed faster >>> than my needs so far. So I can usually bitbang everything or use a >>> peripheral. I used PLDs for glue logic back in the day but that's it. Oh >>> and I bought a small xilinx dev kit which I got to make a led flash then >>> put in a drawer for 15 years. >> >> So your use of MCUs is based on inertia? > > Partly I suppose. > > Or I could say that my projects so far all require a microcontroller > anyway, and it seemed likely that a separate FPGA was always going to be > more expensive than, say, choosing a faster CPU. > > A STM32F4 can bitbang a PIO at 84MHz. (It can't do anything else then, > but still...) I think what you are saying is that the MCU is a key part of your design and you use a lot of code in it. Ok, if your emphasis in on using a commercial MCU that will do the job. But unless your MCU needs are just too large for something that fits in an FPGA, you have it backwards in my opinion. Why have both when you can just use an FPGA? >>> But could you give an example of your $3 one? Or a favorite? >> >> A startup company called Silicon Blue came out with a line of FPGAs >> targeted to the high volume, low power market that exists for portable >> devices. They were preparing their second device family and were >> bought by Lattice Semi. The first family was dropped and the second >> family is the iCE40 (for 40 nm). They are very low power although >> smallish. The largest one has 8 kLUTs, the smallest 384 LUTs. >> >> Last winter I was looking at designing a very low power radio >> controlled clock to run in one of these. They were still playing a >> shell game with the devices in the lineup and the 640 LUT part I >> wanted to use was dropped... :( The only real problem I have with >> these devices is the packaging. Because of the target market the >> packages are mostly fine pitch BGAs. Great if you are making a cell >> phone, not so great if you are designing other equipment. >> >> You can get the 1 kLUT parts for under $3 and possibly the 4 kLUT >> parts. It has been a while since I got a quote. The 1 kLUT part is >> big enough for a soft core MCU plus some custom logic. > > OK, thanks, will check them out. I haven't gotten a quote on these parts since they were bought by Lattice. I'd appreciate a pricing update if you get one. They should be able to do a lot better than the Digikey price, I know Xilinx and Altera always do. Heck, the Digikey pricing for most FPGAs doesn't go above qty 1... if nothing else there should be some quantity price breaks. -- Rick
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| From | John Devereux <john@devereux.me.uk> |
|---|---|
| Date | 2013-09-08 19:04 +0100 |
| Message-ID | <87li37yytr.fsf@devereux.me.uk> |
| In reply to | #13390 |
rickman <gnuarm@gmail.com> writes: > On 9/8/2013 4:04 AM, John Devereux wrote: >> rickman<gnuarm@gmail.com> writes: >> >>> On 9/7/2013 4:24 AM, John Devereux wrote: >>>> rickman<gnuarm@gmail.com> writes: >>>> >>>>> If your FPGA designs are expensive or power hungry, then you are doing >>>>> things you can't do in an MCU or you are not using FPGAs properly. >>>>> They don't need to use any more power than an MCU and in many cases >>>>> less. They certainly don't need to be significantly more expensive >>>>> unless you consider every dollar in your designs. At the very low end >>>>> MCUs can be under $1 and still have reasonable performance. For $1 >>>>> you can't get much in the way of programmable logic. For $3 however, >>>>> you can get a chip large enough for a CPU (with math) and room for >>>>> your special logic. >>>> >>>> I've never used an FPGA, microcontrollers have increased in speed faster >>>> than my needs so far. So I can usually bitbang everything or use a >>>> peripheral. I used PLDs for glue logic back in the day but that's it. Oh >>>> and I bought a small xilinx dev kit which I got to make a led flash then >>>> put in a drawer for 15 years. >>> >>> So your use of MCUs is based on inertia? >> >> Partly I suppose. >> >> Or I could say that my projects so far all require a microcontroller >> anyway, and it seemed likely that a separate FPGA was always going to be >> more expensive than, say, choosing a faster CPU. >> >> A STM32F4 can bitbang a PIO at 84MHz. (It can't do anything else then, >> but still...) > > I think what you are saying is that the MCU is a key part of your > design and you use a lot of code in it. Yes, basically. "a lot" being only e.g. about 64k probably, not much for a MCU but would push the price up for an FPGA I think. > Ok, if your emphasis in on using a commercial MCU that will do the > job. But unless your MCU needs are just too large for something that > fits in an FPGA, you have it backwards in my opinion. Why have both > when you can just use an FPGA? I'm pretty sure that a FPGA with enough RAM would be far too expensive (compared to the $3 200 MIPS CPU). A M3 or M4 with attached FPGA + memories would be interesting, if it was at a reasonable price. NXP have a M4 with attached M0 which sort of goes in that direction; the M0 does the more deterministic simple stuff, the M4 does the number crunching and runs the more complicated software. >>>> But could you give an example of your $3 one? Or a favorite? >>> [...] >>> You can get the 1 kLUT parts for under $3 and possibly the 4 kLUT >>> parts. It has been a while since I got a quote. The 1 kLUT part is >>> big enough for a soft core MCU plus some custom logic. >> >> OK, thanks, will check them out. > > I haven't gotten a quote on these parts since they were bought by > Lattice. I'd appreciate a pricing update if you get one. They should > be able to do a lot better than the Digikey price, I know Xilinx and > Altera always do. Heck, the Digikey pricing for most FPGAs doesn't go > above qty 1... if nothing else there should be some quantity price > breaks. Unfortunately I don't really have a live application, so would only be able to buy them as "education" at this stage. -- John Devereux
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2013-09-08 07:29 -0400 |
| Message-ID | <l0j18v$ph7$1@dont-email.me> |
| In reply to | #13392 |
On 9/8/2013 2:04 PM, John Devereux wrote: > rickman<gnuarm@gmail.com> writes: > >> On 9/8/2013 4:04 AM, John Devereux wrote: >>> rickman<gnuarm@gmail.com> writes: >>> >>>> On 9/7/2013 4:24 AM, John Devereux wrote: >>>>> rickman<gnuarm@gmail.com> writes: >>>>> >>>>>> If your FPGA designs are expensive or power hungry, then you are doing >>>>>> things you can't do in an MCU or you are not using FPGAs properly. >>>>>> They don't need to use any more power than an MCU and in many cases >>>>>> less. They certainly don't need to be significantly more expensive >>>>>> unless you consider every dollar in your designs. At the very low end >>>>>> MCUs can be under $1 and still have reasonable performance. For $1 >>>>>> you can't get much in the way of programmable logic. For $3 however, >>>>>> you can get a chip large enough for a CPU (with math) and room for >>>>>> your special logic. >>>>> >>>>> I've never used an FPGA, microcontrollers have increased in speed faster >>>>> than my needs so far. So I can usually bitbang everything or use a >>>>> peripheral. I used PLDs for glue logic back in the day but that's it. Oh >>>>> and I bought a small xilinx dev kit which I got to make a led flash then >>>>> put in a drawer for 15 years. >>>> >>>> So your use of MCUs is based on inertia? >>> >>> Partly I suppose. >>> >>> Or I could say that my projects so far all require a microcontroller >>> anyway, and it seemed likely that a separate FPGA was always going to be >>> more expensive than, say, choosing a faster CPU. >>> >>> A STM32F4 can bitbang a PIO at 84MHz. (It can't do anything else then, >>> but still...) >> >> I think what you are saying is that the MCU is a key part of your >> design and you use a lot of code in it. > > Yes, basically. "a lot" being only e.g. about 64k probably, not much for > a MCU but would push the price up for an FPGA I think. > >> Ok, if your emphasis in on using a commercial MCU that will do the >> job. But unless your MCU needs are just too large for something that >> fits in an FPGA, you have it backwards in my opinion. Why have both >> when you can just use an FPGA? > > I'm pretty sure that a FPGA with enough RAM would be far too expensive > (compared to the $3 200 MIPS CPU). I won't pretend that an FPGA is the right solution for every task. But I think MCUs are often used because that is what the designer is used to and FPGAs aren't understood well enough to consider. Is "enough" RAM more than what a given FPGA has? I don't know, how much RAM do you really need? Most MCU projects I have worked on never had a realistic RAM estimate, it was all by the seat of the pants. The fact that code uses RAM makes it harder to estimate. FPGAs are a lot easier to design with in that regard. RAM quantities have to be known exactly. LUT counts have to be estimated though, so its not totally different. > A M3 or M4 with attached FPGA + memories would be interesting, if it was > at a reasonable price. Or even an AVR... are you reading Ulf? I think the requirements for MCUs are often overstated. Most of the sort of work I do could be done with an 8051 (ugh!) if one of the higher performance devices especially, but I often don't have the real estate for a separate MCU unless I can treat it as an I/O expander. > NXP have a M4 with attached M0 which sort of goes in that direction; the > M0 does the more deterministic simple stuff, the M4 does the number > crunching and runs the more complicated software. Hell, I'd be estatic if they provided FPGAs in small enough packages so I can use a 32 pin QFN for an MCU and the same footprint for an FPGA. Well, Lattice *does* put an XO2 in a 32 QFN, but only 256 LUTs which is not big enough for much. Why not 1 or 2 or 4 kLUT? For some reason FPGA vendors all think you need more I/O and less LUTs. >>>>> But could you give an example of your $3 one? Or a favorite? >>>> > > [...] > >>>> You can get the 1 kLUT parts for under $3 and possibly the 4 kLUT >>>> parts. It has been a while since I got a quote. The 1 kLUT part is >>>> big enough for a soft core MCU plus some custom logic. >>> >>> OK, thanks, will check them out. >> >> I haven't gotten a quote on these parts since they were bought by >> Lattice. I'd appreciate a pricing update if you get one. They should >> be able to do a lot better than the Digikey price, I know Xilinx and >> Altera always do. Heck, the Digikey pricing for most FPGAs doesn't go >> above qty 1... if nothing else there should be some quantity price >> breaks. > > Unfortunately I don't really have a live application, so would only be > able to buy them as "education" at this stage. I got a freebie eval board for the iCE40 but haven't fired it up. I want to measure some power consumption numbers. The data sheets changed the static current a while back, well after they had been out, just after Lattice bought SiliconBlue so I'm not sure what that was about. The 1 kLUT part went from around 40 uA to 100 uA quiescent current. The dynamic current is still very low though, single digit mA with the device full of 16 bit counters running at 32 MHz. But they seem to have removed that data when they changed data sheet formats. -- Rick
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| From | John Devereux <john@devereux.me.uk> |
|---|---|
| Date | 2013-09-09 08:56 +0100 |
| Message-ID | <87haduzave.fsf@devereux.me.uk> |
| In reply to | #13404 |
rickman <gnuarm@gmail.com> writes: > On 9/8/2013 2:04 PM, John Devereux wrote: >> rickman<gnuarm@gmail.com> writes: >> >>> On 9/8/2013 4:04 AM, John Devereux wrote: >>>> rickman<gnuarm@gmail.com> writes: >>>> >>>>> On 9/7/2013 4:24 AM, John Devereux wrote: >>>>>> rickman<gnuarm@gmail.com> writes: >>>>>> >>>>>>> If your FPGA designs are expensive or power hungry, then you are doing >>>>>>> things you can't do in an MCU or you are not using FPGAs properly. >>>>>>> They don't need to use any more power than an MCU and in many cases >>>>>>> less. They certainly don't need to be significantly more expensive >>>>>>> unless you consider every dollar in your designs. At the very low end >>>>>>> MCUs can be under $1 and still have reasonable performance. For $1 >>>>>>> you can't get much in the way of programmable logic. For $3 however, >>>>>>> you can get a chip large enough for a CPU (with math) and room for >>>>>>> your special logic. >>>>>> >>>>>> I've never used an FPGA, microcontrollers have increased in speed faster >>>>>> than my needs so far. So I can usually bitbang everything or use a >>>>>> peripheral. I used PLDs for glue logic back in the day but that's it. Oh >>>>>> and I bought a small xilinx dev kit which I got to make a led flash then >>>>>> put in a drawer for 15 years. >>>>> >>>>> So your use of MCUs is based on inertia? >>>> >>>> Partly I suppose. >>>> >>>> Or I could say that my projects so far all require a microcontroller >>>> anyway, and it seemed likely that a separate FPGA was always going to be >>>> more expensive than, say, choosing a faster CPU. >>>> >>>> A STM32F4 can bitbang a PIO at 84MHz. (It can't do anything else then, >>>> but still...) >>> >>> I think what you are saying is that the MCU is a key part of your >>> design and you use a lot of code in it. >> >> Yes, basically. "a lot" being only e.g. about 64k probably, not much for >> a MCU but would push the price up for an FPGA I think. >> >>> Ok, if your emphasis in on using a commercial MCU that will do the >>> job. But unless your MCU needs are just too large for something that >>> fits in an FPGA, you have it backwards in my opinion. Why have both >>> when you can just use an FPGA? >> >> I'm pretty sure that a FPGA with enough RAM would be far too expensive >> (compared to the $3 200 MIPS CPU). > > I won't pretend that an FPGA is the right solution for every task. > But I think MCUs are often used because that is what the designer is > used to and FPGAs aren't understood well enough to consider. Is > "enough" RAM more than what a given FPGA has? I don't know, how much > RAM do you really need? Most MCU projects I have worked on never had > a realistic RAM estimate, it was all by the seat of the pants. It's not always known how much you need, you discover things during development, rework algorithms, sometimes trade RAM for speed. Customers want more features. > The fact that code uses RAM makes it harder to estimate. FPGAs are a > lot easier to design with in that regard. RAM quantities have to be > known exactly. Hmm, now that really sounds like turning a constraint into a feature! > LUT counts have to be estimated though, so its not totally different. > > >> A M3 or M4 with attached FPGA + memories would be interesting, if it was >> at a reasonable price. > > Or even an AVR... are you reading Ulf? I think the requirements for > MCUs are often overstated. Most of the sort of work I do could be > done with an 8051 (ugh!) if one of the higher performance devices > especially, but I often don't have the real estate for a separate MCU > unless I can treat it as an I/O expander. Yes, if you have a powerful FPGA you could use a less powerful CPU usually. >> NXP have a M4 with attached M0 which sort of goes in that direction; the >> M0 does the more deterministic simple stuff, the M4 does the number >> crunching and runs the more complicated software. > > Hell, I'd be estatic if they provided FPGAs in small enough packages > so I can use a 32 pin QFN for an MCU and the same footprint for an > FPGA. Well, Lattice *does* put an XO2 in a 32 QFN, but only 256 LUTs > which is not big enough for much. Why not 1 or 2 or 4 kLUT? For some > reason FPGA vendors all think you need more I/O and less LUTs. > > >>>>>> But could you give an example of your $3 one? Or a favorite? >>>>> >> >> [...] >> >>>>> You can get the 1 kLUT parts for under $3 and possibly the 4 kLUT >>>>> parts. It has been a while since I got a quote. The 1 kLUT part is >>>>> big enough for a soft core MCU plus some custom logic. >>>> >>>> OK, thanks, will check them out. >>> >>> I haven't gotten a quote on these parts since they were bought by >>> Lattice. I'd appreciate a pricing update if you get one. They should >>> be able to do a lot better than the Digikey price, I know Xilinx and >>> Altera always do. Heck, the Digikey pricing for most FPGAs doesn't go >>> above qty 1... if nothing else there should be some quantity price >>> breaks. >> >> Unfortunately I don't really have a live application, so would only be >> able to buy them as "education" at this stage. > > I got a freebie eval board for the iCE40 but haven't fired it up. I > want to measure some power consumption numbers. The data sheets > changed the static current a while back, well after they had been out, > just after Lattice bought SiliconBlue so I'm not sure what that was > about. The 1 kLUT part went from around 40 uA to 100 uA quiescent > current. The dynamic current is still very low though, single digit > mA with the device full of 16 bit counters running at 32 MHz. But > they seem to have removed that data when they changed data sheet > formats. -- John Devereux
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