deltabeard / cmio

Custom Raspberry Pi Compute Module (1/3) IO Board
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SD Card require pull-ups #21

Open deltabeard opened 5 years ago

deltabeard commented 5 years ago

CMD and DATA lines D0-D3 of the slave SD Card should be pulled up by 50KOhm resistor even in 1-bit mode or SPI mode. The pullups of the slave cards should be connected even if they’re not connected to the host.

Adapted from: https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/sd_pullup_requirements.html