[Solved] SdFat library and SS

Using Arduino Storage
1

In ReadWrite.ino, there is the definition #define SD_CS_PIN SS.

In which file is the value SS defined ?

I have to change SS to 4 in the sketch ( #define SD_CS_PIN 4 ) in order for the SeeedStudio SD Card Shield to work.

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2

SS usually defined in the Arduino library. For the Uno it is pin 10.

3

Thank you.

4

SS is defined in the pins_arduino.h file for the variant (as defined in boards.txt) of the currently selected board. For example, if you are compiling for Uno, you can see it uses the standard variant:

uno.build.variant=standard

Then if you open variants/standard/pins_arduino.h:

#define PIN_SPI_SS    (10)
#define PIN_SPI_MOSI  (11)
#define PIN_SPI_MISO  (12)
#define PIN_SPI_SCK   (13)

static const uint8_t SS   = PIN_SPI_SS;