any raspberry pi people here?...

[server]

DecadentLinuxUserNumeroUno@decadence.org wrote in news:tc36r3$14r9$1
@gioia.aioe.org:

albert@cherry.(none) (albert) wrote in
news:nnd$224d213a$6ed2eb7a@d7dff6696c7ccdd2:

In article <ilhbdhp4i6lcl486j5u3gijh9a7mbrej9c@4ax.com>,
John Larkin <xx@yy.com> wrote:
On Mon, 18 Jul 2022 22:23:21 +0300, Dimiter_Popoff
dp@tgi-sci.com> wrote:

On 7/18/2022 22:13, John Larkin wrote:


The pi doesn\'t seem to have any general counter/timer hardware,
like ARMs usually do. I\'ve seen vague references to using the
GPU to do timings.

I\'d like to measure frequencies and timestamp some edges, in
the 1 us sort of domain, several channels. I guess we could
hang a small FPGA off to the side if pi can\'t do it.

Do pi\'s have crystal oscillators? I guess we could add one too.




Are you serious about using yet another aliexpress toy for some
real design?

https://en.wikipedia.org/wiki/Raspberry_Pi

Not exactly a toy. But it would save us using up our stock of
FPGAs and ARM chips, and I know a guy who would like to do the
programming. He\'s a retired Fellow of United Technologies
(Collins) who really likes to code.


Other than the obvious question above, does not ARM have some
sort of timebase register as part of the core? This might be
usable to some extent, depending on how much jitter you can
tolerate.

The ARM in the pi seems to have none of the usual counter/timer
stuff, so we\'d have to do that externally, in a small FPGA
probably. We might have three frequency counters and maybe six
edge time stampers in a FIFO or something. Pretty simple.

The Raspberry pi 1 has a 64 bit counter offset 0x9100 in the
Virtual Memory IO Space
This is the Forth code, fetching a double precision number
of the addres

: TICKS ^clk 2@ ;

This seems to be more reliable of the counters in the Intel.
It is running at 1 Mhz.
Others pi\'s (Orange pi) have similar counters.


Some torque sensors make tricky timing waveforms.


Groetjes Albert

Check out the new pico W rPi...

https://www.raspberrypi.com/news/raspberry-pi-pico-w-your-6-iot-
platform/

Even better!

<https://www.raspberrypi.com/products/raspberry-pi-zero-2-w/>