Pi Pico Python speed

[john larkin]

Has anyone measured how fast a pico can do things running Python?
Like, to start, wiggling a port pin as fast as possible?

I think the micro Python is an interpreter.

[Peter Heitzer]

Yes, Python is interpreted.
I found https://wellys.com/posts/board-language_speed/
I think the performance of Micropython and Circuitpython should be
almost equal.
The nice thing is that you can test your code interactively in the
Python interpreter.


--
Dipl.-Inform(FH) Peter Heitzer, peter....@rz.uni-regensburg.de

[john larkin]

On 8 Feb 2024 08:10:20 GMT, "Peter Heitzer"

<peter....@rz.uni-regensburg.de> wrote:

>john larkin <j...@650pot.com> wrote:
>>Has anyone measured how fast a pico can do things running Python?
>>Like, to start, wiggling a port pin as fast as possible?
>
>>I think the micro Python is an interpreter.
>Yes, Python is interpreted.
>I found https://wellys.com/posts/board-language_speed/
>I think the performance of Micropython and Circuitpython should be
>almost equal.
>The nice thing is that you can test your code interactively in the
>Python interpreter.

Cool. We just did a MicroPython loop to raise and lower a port pin 4
times, brute force inline code, as fast as we could. One up/down cycle
takes about 14 microseconds on a Pico, with some jitter.

We'll repeat it in c. I'm guessing that will be 20x faster.

[Bryan]

A little off topic, but do you have any suggestions as to good "I don't
know squat and I'm old and it doesn't make sense" learn MicroPython
resources?

[Peter Heitzer]

I did a quick test yesterday evening using this few lines of code:

from machine import Pin
led=Pin(0,Pin.OUT)
switch=Pin(1,Pin.IN,Pin.PULL_UP)
while switch.value(): led.toggle()

GPIO0 was an output driving a LED. On GPIO1 I connected a momentary switch
to ground. On the output pin I got about 41 kHz until the switch was
pressed. With an endless loop:
while True: led.toggle()
I got 83 kHz.
I used Micropython v. 1.20; the Pico run at 125 MHz.
I also noticed some jitter. Normally one would not create a rectangle signal
this way but use a PWM channel for that task.

[Andy Burns]

Peter Heitzer wrote:

> john larkin wrote:
>
>> Cool. We just did a MicroPython loop to raise and lower a port pin 4
>> times, brute force inline code, as fast as we could. One up/down cycle
>> takes about 14 microseconds on a Pico, with some jitter.
>
>> We'll repeat it in c. I'm guessing that will be 20x faster.
>
> I did a quick test yesterday evening using this few lines of code:

> I got 83 kHz.

I think if you want the fastest cycle time, you'd use the RP2040's PIO
state machine, and probably get 62MHz without overclocking, but then
that's not really testing MicroPython ...

[Peter Heitzer]

Although the PIO code could be written in MicroPython with the
decorator @rp2.asm_pio().

[Andy Burns]

Peter Heitzer wrote:

> the PIO code could be written in MicroPython with the decorator
> @rp2.asm_pio().

I should get a Pico to play with ...

[The Natural Philosopher]

The worst part is getting a toolchain working: and understanding the
APIs. If you don't want to use Python.

Coding the little fuckers is pretty simple after that.


--
"What do you think about Gay Marriage?"
"I don't."
"Don't what?"
"Think about Gay Marriage."