Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.arch.embedded > #29468

Re: Custom CPU Designs

From Grant Edwards <invalid@invalid.invalid>
Newsgroups comp.arch.embedded
Subject Re: Custom CPU Designs
Date 2020-04-16 22:01 +0000
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <r7akkb$i37$1@reader2.panix.com> (permalink)
References <abb9b585-5a14-45d0-b617-543a009a176c@googlegroups.com> <xrB*I6GPx@news.chiark.greenend.org.uk> <r79lfe$j7d$2@reader2.panix.com> <urB*mlJPx@news.chiark.greenend.org.uk>

Show all headers | View raw

On 2020-04-16, Theo <theom+news@chiark.greenend.org.uk> wrote:

> - if you have the space it's better to use an on-chip BRAM rather
>   than SDRAM, given the SDRAM is often running at ~100MHz x 16 bits,
>   which makes even instruction fetch multi-cycle.  DDR is better but
>   the memory controllers are much more complex, and life gets easier
>   when you have cache.

I don't remember if we ever got it to work reliably at 100M
full-duplex.  I know it was close, and it worked OK half-duplex.  I do
remember there was a _lot_ of messing around with interleave, burst
length, etc.

> - they've upgraded to a plugin for a modern version of Eclipse
>   rather than a fork from 2005, but it's still Eclipse :( I just
>   drive the shell scripts directly (although the pile of Make they
>   generate isn't that nice).  I've never had it need a dongle.

IIRC, we eventually got to the point where we only needed the dongle
when the HW guys changed something and the register map changed.  I
ended up writing several scripts so we could use plain old Makefiles
after the register maps had been generated.

> - the JTAG interface is horrible and I've spent way too much time
>   reverse engineering it[1] and working around its foibles, in
>   particularly the JTAG UART which is broken in several ways (google
>   'JTAG Atlantic' for some workarounds)

Once I got a UART working so I count print messages, I just gave up on
the JTAG BS.  Another interesting quirk was that the Altera USB JTAG
interface only worked right with a few specific models of powered USB
hubs.

>> After spending a year developing prototype products that would never
>> quite work, we abandoned the NIOS2 in favor of an NXP Cortex M3.
>
> These days a RISC-V CPU in FPGA solves a lot of the horrible
> proprietaryness, although you still have to glue the toolchain
> together yourself (git clone riscv-gcc).
>
> But if you can do the job with a hard MCU I can't see why you'd want
> an FPGA.

We needed a pretty decent-sized FPGA for custom peripherals and an I/O
processor.  So, Altera sold somebody on the idea of moving the uC into
the FPGA also.

> Personally I much prefer the ARM cores on FPGAs these days - they're a
> Proper CPU that Just Works.

Definitely. The M-class parts are so cheap, there's not much point in
thinking about doing it in an FPGA.

> [1] Did you know the Altera product codenames were based on dragons from How
> to Train Your Dragon?  Interesting what you find out when running strace(1)
> on the binary...

I did not know that. :)

--
Grant

Back to comp.arch.embedded | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-15 20:51 -0700
  Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-16 11:59 +0100
    Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-16 13:28 +0200
    Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-16 13:10 +0000
      Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-16 22:16 +0100
        Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-16 22:01 +0000
          Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-16 17:13 -0700
            Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-16 18:10 -0700
            Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 18:37 -0700
              Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-16 22:08 -0700
              Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 10:02 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-17 10:49 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 15:44 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-17 15:23 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 18:15 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-17 17:49 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-18 15:06 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-18 16:08 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:13 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 14:24 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 16:00 +0200
                Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-20 14:32 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 23:55 +0100
                Re: Custom CPU Designs Reinhardt Behm <rbehm@hushmail.com> - 2020-04-21 15:14 +0800
                Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-18 16:51 +0100
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-18 18:06 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 14:53 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 10:11 +0100
                Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-19 13:19 +0300
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 11:33 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:26 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 14:59 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 13:37 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 22:02 +0100
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 22:15 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 15:02 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 02:03 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 14:44 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:20 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 14:57 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 12:38 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:58 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 16:27 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 17:36 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 14:02 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 06:15 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 17:25 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 16:56 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 12:42 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 23:16 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 11:10 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 08:09 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 20:07 +0200
                Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-18 13:09 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-18 21:28 +0100
                Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-21 20:29 +0300
                Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-21 18:10 +0000
                Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-22 09:54 +0300
                Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 13:19 +0000
                Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-22 18:09 +0300
                Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 17:03 +0000
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 11:16 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 10:48 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-18 16:57 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 14:21 -0700
                Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-18 14:50 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 16:32 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 18:12 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 10:09 +0100
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 16:31 +0100
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 16:42 +0100
                Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-18 00:43 +0300
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-18 17:07 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 09:11 -0700
                Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-17 12:17 -0700
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 13:22 -0700
                Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-17 14:48 -0700
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 15:27 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 16:53 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 17:03 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 19:39 +0200
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 21:25 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 18:27 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 17:58 +0200
                Re: Custom CPU Designs Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-04-21 19:41 +0300
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 14:01 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 23:21 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-19 20:53 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 14:47 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 02:11 +0100
                Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-19 18:31 -0700
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 20:32 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 07:46 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 00:33 -0700
                Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 11:01 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 17:44 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 19:57 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 18:02 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 14:56 -0700
            Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-17 16:34 +0100
              Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 17:57 +0200
                Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-21 15:20 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 08:26 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 18:09 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 15:00 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 11:28 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 08:24 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 20:18 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 11:45 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-23 17:47 +0200
                Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-21 15:35 -0700
            Re: Custom CPU Designs Przemek Klosowski <przemek@tux.dot.org> - 2020-04-19 18:52 +0000
              Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 13:42 -0700
              Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-20 22:59 +1000
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 17:01 -0700
                Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-21 10:23 +1000
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 03:47 -0700
                Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-22 09:26 +1000
                Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-22 22:06 +0100
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 14:18 -0700
                Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-23 22:35 +0100
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 18:20 +0200
                Re: Custom CPU Designs Dimiter_Popoff <dp@tgi-sci.com> - 2020-04-22 18:16 +0300
                Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 17:06 +0000
                Re: Custom CPU Designs Dimiter_Popoff <dp@tgi-sci.com> - 2020-04-22 20:17 +0300
                Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 17:28 +0000
                Re: Custom CPU Designs George Neuner <gneuner2@comcast.net> - 2020-04-23 04:59 -0400
                Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-20 17:27 -0700
              Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 17:58 +0200
                Re: Custom CPU Designs pault.eg@googlemail.com - 2020-04-21 01:00 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 19:21 +0200
          Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-17 17:18 +0100
    Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 07:40 -0700
      Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-16 12:28 -0700
        Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 13:50 -0700
          Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-16 14:19 -0700
          Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-16 22:33 +0100
    Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-17 11:29 +1000
      Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 18:42 -0700
        Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-17 12:35 +1000
          Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 20:01 -0700
            Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-17 14:54 +1000
              Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 23:54 -0700
              Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 10:38 +0200
                Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 09:13 -0700
                Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 18:02 +0200

csiph-web