> On 17 Feb 2022, at 20:04, Daniel Braniss <[email protected]> wrote:
>> On 17 Feb 2022, at 11:30, Daniel O'Connor <[email protected]> wrote:
>>
>>> On 17 Feb 2022, at 19:50, Daniel Braniss <[email protected]> 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?
> m5 stamp C3U
> https://shop.m5stack.com/products/m5stamp-c3u-mate-with-pin-headers?_pos=2&_sid=3df9b5f0d&_ss=r&variant=42341016633601
According to the docs the 'U' variant doesn't have a serial chip on it. If you
look at the schematic the USB +/- pins go straight to the MCU.
I suspect it has a boot loader which emulates the CH9102, when your code is
running it is whatever that does with the USB port, so if there is a bug or
whatever then it will exhibit weird behaviour.
--
Daniel O'Connor
"The nice thing about standards is that there
are so many of them to choose from."
-- Andrew Tanenbaum
