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Re: is the java compiler written in c

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On 8/21/2015 6:32 PM, Martin Gregorie wrote:
> On Fri, 21 Aug 2015 16:51:00 -0500, BGB wrote:
>
>> one could be like, "how does one do anything with only a few kB of
>> ROM?", but it partly is a matter of perspective. if you expect to use a
>> big complex program, it wont work. if can do everything in maybe a few
>> hundred lines of C (sans comments), then, say, a 2kB ROM space and 256B
>> of RAM is sufficient.
>>
> Slightly OT I know, but it can be an interesting experience to get
> something running on a Parallax BS2  - its programmed in P-coded integer
> BASIC with room doe maybe 200 lines of code and has 32 bytes of RAM,
> which includes the memory-mapped I/o ports However, at least to can store
> constants in the flash memory that holds the user code. If you think it
> out appropriately you can do more than you can expect, not least because
> variables can be 1,2 or 8 bits in length.
>
> I've not (yet) used one, but I'd imagine that using a PICAXE chip would
> be quite similar.
>

yeah, I have mostly recently been messing with MSP430G2232 chips (2kB 
ROM, 256kB RAM, 8ch ADC).

despite their seemingly trivial sized ROM, I have used one essentially 
for a simplistic 3-phase VFD. it has both 2 and 3 phase outputs, 
selectable mode/direction (currently 8 modes and forward/reverse, modes 
select between 2 and 3 phase and wave-function), and logic for doing 
voltage regulation (*).

though, ironically, in a VFD like this, the transistors work out to a 
lot more expense than the controllers (you can use expensive MOSFETs or 
cheaper BJTs, but one is looking at bulk prices of around $0.60 for the 
MCU, and about $1 for each MOSFET).


*: DC->DC conversion being used to create a specific voltage for the 
output rail (may vary based on drive frequency). at present, this would 
be for doing 12V -> 55V which is needed for approx 24 VAC output, where 
a little over 2x the target voltage is needed for 3-phase.

3-phase requires a rail-voltage of roughly the peak-to-peak voltage, 
which would work out to 68v for a sine-wave. however, if the wave 
function is tweaked some (say, so RMS is closer to 0.9 P-P vs 0.71 P-P), 
then a 55V rail is sufficient (and this is in-turn due to otherwise 
needing more expensive transistors).

though, doing a VFD with a UI and/or a control protocol would likely 
still require a bigger MCU.

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is the java compiler written in c gdotone@gmail.com - 2015-08-19 12:41 -0700
  Re: is the java compiler written in c Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-08-19 16:06 -0400
    Re: is the java compiler written in c gdotone@gmail.com - 2015-08-19 16:12 -0700
      Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-20 11:08 +0000
        Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-20 20:34 -0400
      Re: is the java compiler written in c Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-08-20 07:44 -0400
      Re: is the java compiler written in c e.d.programmer@gmail.com - 2015-08-20 06:36 -0700
        Re: is the java compiler written in c gdotone@gmail.com - 2015-08-20 18:58 -0700
          Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-20 22:13 -0400
            Re: is the java compiler written in c g g <gdotone@gmail.com> - 2015-08-20 19:57 -0700
              Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-21 21:25 -0400
      Re: is the java compiler written in c Eternal Hope <laughingspam99@gmail.com> - 2015-08-21 08:15 +0100
        Re: is the java compiler written in c e.d.programmer@gmail.com - 2015-08-21 06:56 -0700
          Re: is the java compiler written in c Eternal Hope <laughingspam99@gmail.com> - 2015-08-21 15:32 +0100
        Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-21 16:51 -0500
          Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-21 23:32 +0000
            Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-21 23:35 -0500
          Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-21 22:39 -0400
            Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-21 22:42 -0500
              Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-22 11:41 +0000
                Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-22 10:03 -0500
              Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-30 22:03 -0400
                Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-31 01:09 -0500
                Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-09-03 20:46 -0400
                Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-09-04 10:01 -0500
            Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-22 11:37 +0000
              Re: is the java compiler written in c Eternal Hope <laughingspam99@gmail.com> - 2015-08-22 12:56 +0100
                Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-22 18:04 +0000
                Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-22 14:27 -0500
              Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-30 22:06 -0400
          Re: is the java compiler written in c Eternal Hope <laughingspam99@gmail.com> - 2015-08-22 10:31 +0100
            Re: is the java compiler written in c BGB <cr88192@hotmail.com> - 2015-08-23 01:31 -0500
        Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-21 22:42 -0400
          Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-22 11:53 +0000
            Re: is the java compiler written in c Eternal Hope <laughingspam99@gmail.com> - 2015-08-22 13:11 +0100
              Re: is the java compiler written in c Martin Gregorie <martin@address-in-sig.invalid> - 2015-08-22 17:55 +0000
                Re: is the java compiler written in c Eternal Hope <laughingspam99@gmail.com> - 2015-08-22 19:59 +0100
            Re: is the java compiler written in c Gene Wirchenko <genew@telus.net> - 2015-08-26 09:44 -0700
              Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-30 22:11 -0400
  Re: is the java compiler written in c Arne Vajhøj <arne@vajhoej.dk> - 2015-08-19 19:35 -0400

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