Metro RP2350 10.x SD_CS in use

[mikeysklar]

CircuitPython version and board name

Adafruit CircuitPython 10.0.0-alpha.6 on 2025-05-17; Adafruit Metro RP2350 with rp2350b

Code/REPL

Adafruit CircuitPython 10.0.0-alpha.6 on 2025-05-17; Adafruit Metro RP2350 with rp2350b
>>>
soft reboot

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
Traceback (most recent call last):
  File "code.py", line 25, in <module>
ValueError: SD_CS in use

Behavior

Guide example SD code for the Metro RP2350 works well with CircuitPython 9.2.8 for read / write.

Fails with CircuitPython 10-alpha6 on "SD_CS in use".

Description

Forum issue easily reproduced.

Additional information

No response

[todbot]

I was noticing this too today. Is there the equivalent of displayio.release_displays() for built-in SD card? Otherwise, the entire SD Card section of the Metro RP2350 Learn Guide needs to be greatly modified.

[mikeysklar]

Thx @todbot. At first I thought it would be an easy work around with some minor syntax changes or using sdioio, but even with some vibe coding no love on 10.x.

Love the CP podcast, BTW.

[FoamyGuy]

I think the CircuitPython core may be initializing the SDCard automatically in the 10.x versions branch which is why it reports the pin is already in use.

It's worth trying to just start using the SDCard from your code at its mount point /sd/ as if it's already mounted to see if that works.

We do still need to update the guide though to make clear which versions have which behavior. And ideally try to update the examples with error handling to support both versions.

[mikeysklar]

@FoamyGuy Thank you I will update the guide with a 10.x warning and sample code. I was able to confirm that a minimal write test worked just fine with 10.x

import time
import microcontroller

print("Logging temperature to /sd/temperature.txt")

while True:
    t = microcontroller.cpu.temperature
    print("T = %0.1f °C" % t)
    with open("/sd/temperature.txt", "a") as f:
        f.write("%0.1f\n" % t)
    time.sleep(1)

[mikeysklar]

Closing this issue.

The guide code has been updated (Foamy version).

Change in behavior with CP 10.x offering automatic SD mounting on this board model.