QUERY · ISSUE

ESP32: SDCard throws Errors

openby Narsskrarcopened 2022-02-10updated 2024-09-08

needs-info

Hi,

I try to access a SD card with MP V 1.18. The reader is connected to slot 2. The hardware seem to work (tested with an ESP32 with C code). It's a 8GB SDHC formatted with FAT32.

I do
sd = SDCard(slot=2)

Now
sd.info()
throws
OSError: (-265, 'ESP_ERR_INVALID_CRC')

and
os.mount(sd, "/sd")
throws
OSError: 16

16 seems to be EBUSY, although this errorcode isn't defined in errno.errorcode... and it doesn't help me either.

What can I do to investigate what goes wrong?

Thanks.

CANDIDATE · ISSUE

ESP32 Cannot mount SD Card on Wemos LOLIN D32 Pro V2.0.0

closedby phuzybunyopened 2021-07-03updated 2025-02-11

port-esp32

Firmware:

esp32spiram-20210623-v1.16.bin

Board:

Wemos LOLIN D32 Pro V2.0.0, ESP32-WROVER, ESP32-D0WDQ6 (revision 1)

According the Wemos D32 Pro Schematic and verified using a continuity meter, the SD card pins are as follows:

SCK: GPIO18
MOSI: GPIO23
MISO: GPIO19
CS: GPIO4

Trying to mount the SD card but encountering the following error:

>>> import uos, machine
>>> uos.mount(machine.SDCard(slot=2, width=1, sck=18, mosi=23, miso=19, cs=4), '/sd')
E (61965) sdmmc_sd: sdmmc_init_spi_crc: sdmmc_send_cmd_crc_on_off returned 0x106
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: 16

Assessment

S Sonnet · medium

Both issues report ESP32 SD card mounting failures involving CRC errors and OSError 16 on slot=2. The symptom pattern is nearly identical: CRC failure during sdmmc initialization → OSError 16 (EBUSY). Error codes are adjacent (ESP_ERR_INVALID_CRC=0x105 vs 0x106). However, the configurations differ meaningfully: #8290 uses default slot=2 parameters (likely native SDMMC mode), while #7484 explicitly uses width=1 (SPI mode) with manually specified GPIO pins on a Wemos LOLIN D32 Pro. These are different driver code paths, so the root cause may not be identical. Neither issue references the other, and neither appears resolved. They share a component and symptom pattern but likely represent distinct manifestations of ESP32 SD card initialization fragility rather than the same bug.

Suggested action

Link the two issues for cross-reference. Both need hardware diagnostics (logic analyzer on the SPI/SDMMC lines to confirm whether the CRC error is electrical or protocol-level). Maintainer should check if a known ESP-IDF SD initialization fix covers both paths. Do not close either.

ESP32: SDCard throws Errors

ESP32 Cannot mount SD Card on Wemos LOLIN D32 Pro V2.0.0

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