Cannot open ADC-24 directly after plugging it into a USB port

ehliar · Post by **ehliar** » Tue Mar 26, 2019 9:20 am

I have a problem when trying to use the ADC-24 from Linux using the
picohrdlCon.c example software. Directly after connecting the device I
am unable to open it from picohrdlCon. I'm not sure exactly what is
going on here, but my guess based on the kernel messages in dmesg is
that libpicohrdl downloads firmware for the device but for some reason
cannot open it after the firmware has been downloaded. (If i ctrl-c
picohrdlCon and start it again I am able to open the device in
picohrdlCon.)

In this case the dmesg looks as follow:

*** Here I plug in the device ***

Code: Select all

[3619539.665226] usb 1-9: new full-speed USB device number 67 using xhci_hcd
[3619539.813533] usb 1-9: New USB device found, idVendor=0ce9, idProduct=1003
[3619539.813534] usb 1-9: New USB device strings: Mfr=0, Product=0, SerialNumber=0

*** At this point I start picohrdlCon ***

Code: Select all

[3619572.753634] usb 1-9: USB disconnect, device number 67
[3619574.540823] usb 1-9: new full-speed USB device number 68 using xhci_hcd
[3619574.689446] usb 1-9: New USB device found, idVendor=0ce9, idProduct=1003
[3619574.689452] usb 1-9: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[3619574.689457] usb 1-9: Product: Pico HRDL
[3619574.689460] usb 1-9: Manufacturer: Pico

For this I do not yet have a good workaround, I guess I could try to
open the device from a separate thread and kill that thread in case it
is not able to open the device within 10 seconds or so and then retry
the open. Do you have a better solution or workaround for this?

(By the way, one convenient way to solve the firmware downloading
problem on Linux is to call a firmware downloader such as fxload from
the UDEV rules when the device is plugged in.)