Reply To: Host running less than 16MHz

[Michael P. Flaga]

Note that the SdFat Lib and SFEMP3 lib both set the SPI Mode and Rate just prior to each transfer. This will over write anything you configure. Since each library/driver has a different maximum rate. In early days of SFEMP3 it was configured just at ::begin. But the SdCard changes it to 8Mg and the VS1053 limited to 6 Mg for read back.

It is good practice to not rely on the assumption the SPI is the way you left it. Some other driver may have changed it. Such as adding a SPI Temp Probe or other. Hence your driver should set it prior to enabling the Chip Select.