Re: usb CH9102 serial chip

From: Daniel O'Connor <darius_at_dons.net.au>
Date: Thu, 17 Feb 2022 09:30:33 UTC 

> On 17 Feb 2022, at 19:50, Daniel Braniss <danny@cs.huji.ac.il> wrote:
> 
>> If that is the case then the chip/driver are working fine since that requires bidirectional communication etc..
>> 
> 
> but that works only if I power up the board while pressing a button, then it also appears as /dev/ttyU0, and
> so then I can flash, after reset, the device is gone and there are errors ( BTW, the flashed image workes):
> 
> Feb 17 09:46:59 pampero kernel: usbd_setup_device_desc: getting device descriptor at addr 4 failed, USB_ERR_IOERROR
> Feb 17 09:47:00 pampero kernel: usbd_req_re_enumerate: addr=4, set address failed! (USB_ERR_IOERROR, ignored)

What sort of dev board is it?

Seems very strange the USB UART would behave differently unless it's wired up in an unusual way IMO.

--
Daniel O'Connor
"The nice thing about standards is that there
are so many of them to choose from."
 -- Andrew Tanenbaum