How can 2 picos communicate using USB

[destatez]

I’ve got 2 Picos that are tied to a USB hub, for power. I’d like one of those to transmit text data to the other using the USB. Can I just set Pico1 to use its uart0 for transmit and Pico2 to use its uart1 for receive? I only need communication in this one direction. This seems too simple to get the two Picos talking over USB. Is there something else I should do?

[destatez]

This isn’t an answer, it’s a clarification. I have forgotten how to mod the initial discussion. I’m using MicroPython for the programming language for both.

[GitHubsSilverBullet]

I'd like to submit the idea that a requested (and reported) baudrate of 125Mbaud and a real achieved baudrate of 7.8Mbaud is a tad more than a slight/minor difference. ;-)

[robert-hh]

@GitHubsSilverBullet Just a note: I added a commit to an existing open PR. With that change, an exception is raised if a baud rate cannot be set with an error less than about 2%. In my tests, that happens only for too low or too high baud rates. The test covered >1170 baud rates in the range from 120 baud to 7_812_500 baud.

[GitHubsSilverBullet]

@robert-hh Thanks for that.
As a matter of fact I found something far more serious in the UART part of the ›machine‹ implementation.
Rather interesting that apparently nobody stumbled over it.
I'm currently traveling, so have no lab equipment. Just a PiPico dangling from the USB cable. But that's plenty enough to demonstrate. Wrote a logger with single cycle resolution (using the PIO).
Need another day or two and will then provide a complete test program (might be lengthy, so it needs some documentation)
Btw. Tested on 1.21.1

[robert-hh]

1.21.0 or 1.22.1? You should test with 1.22.1.

[GitHubsSilverBullet]

Sorry. Typo!
MPY: soft reboot
MicroPython v1.22.1 on 2024-01-05; Raspberry Pi Pico with RP2040
Type "help()" for more information.