Re: arm7 core with fast monolithic 12-bit ADC

On Feb 13, 10:37 am, emeb <ebromba...@xxxxxxxxx> wrote:
On Feb 12, 1:47 pm, John Devereux <j...@xxxxxxxxxxxxxx> wrote:





rickman <gnu...@xxxxxxxxx> writes:

[...]

Yeah, that is what I am thinking.  I guess you started out asking for
practical advice and this turned into a discussion of theory.  The
best answer I can give is the ADI ARM7 microverter parts.  They have
the best ADC/DAC in an ARM MCU that I am aware of.  I think someone
else already mentioned these parts.  They are only so-so in the MCU
department, at least in terms of speed.  But speed is not always what
a design is about.

I get the impression that they took a pretty good ADC (+ good DACs),
and managed to get a mediocre ARM onto the same die.

Whereas the other manufacturers have higher performance ARMs, with
better peripherals - except for their mediocre ADCs.

That's a pretty good summary. I've done some work with the ADI
ADuC7026 part and while the analog I/O is good (4 parallel DACs!), the
ARM processor is hamstrung:

* No DMA - all I/O must be programmed through the CPU
* No VIC - Only IRQ/FIQ available and vectoring must be done in
firmware
* Program flash is only 16-bits wide - must use Thumb mode for zero
wait state code access
* SPI interface is limited to ~3MHz clock rate, 8-bits only.

On the upside this part has a parallel external memory bus that comes
in hand for some kinds of interfacing, and it's pretty easy to develop
for. Just don't expect screaming fast performance. I ended up porting
the application intended for the ADuC7026 to a Microchip dsPIC with a
quad SPI DAC and saw about a 2x improvement in throughput.

but does that really matter?
.

Relevant Pages

  • Re: arm7 core with fast monolithic 12-bit ADC
    ... best answer I can give is the ADI ARM7 microverter parts. ... I get the impression that they took a pretty good ADC (+ good DACs), ... and managed to get a mediocre ARM onto the same die. ... SPI interface is limited to ~3MHz clock rate, ...
    (comp.arch.embedded)
  • Re: arm7 core with fast monolithic 12-bit ADC
    ... best answer I can give is the ADI ARM7 microverter parts. ... I get the impression that they took a pretty good ADC (+ good DACs), ... and managed to get a mediocre ARM onto the same die. ... SPI interface is limited to ~3MHz clock rate, ...
    (comp.arch.embedded)
  • Re: arm7 core with fast monolithic 12-bit ADC
    ... best answer I can give is the ADI ARM7 microverter parts. ... and managed to get a mediocre ARM onto the same die. ...
    (comp.arch.embedded)