next topic »

[on:]

Is there a reason this can't be done or has no one tried it? I can't find a single instance of it being used. All SD shields require using SPI mode. I really don't get it. SPI mode is supposedly slower the one-bit or four-bit mode, and one-bit mode is the only mode required by SDA on microSD cards. The reason I ask is I am using the pins used for SPI for a audio output

[Reply #1 on:]

There is no hardware support for SD 1-bit mode so only slow bit-bang would work.  In SD bus mode CRC is required and this is also slow on the Arduino.

You can use bit-bang SPI with the SD.h library and SdFat.

For SD.h edit Sd2Card.h to enable software SPI and define the pins to be used.

Most MicroSD cards support SPI.