File content as of revision 0:48b56cad57ae:

#include "mbed.h"
 
SPI spi(D11, D12, D13); // mosi, miso, sclk
DigitalOut chipSelect(D10);
 
Serial pc(USBTX, USBRX); // tx, rx
 
int main() {
 
    int valueToSendToSlave = 20; // Starting value only, this increments
    spi.format(8,3);        // Setup:  bit data, high steady state clock, 2nd edge capture
    spi.frequency(1000000); //1MHz
 
    pc.printf("======================================================\r\n");
    pc.printf("Press any key to start...\r\n");
    pc.getc(); // wait for keyboard
 
    int counter = 1;
    while (1) {
 
        pc.printf("%d Value to send = %d ", counter++, valueToSendToSlave);
        
        chipSelect = 0; // Select device
        int dataFromSlave =  spi.write(valueToSendToSlave);
        chipSelect = 1; // Deselect device
 
        pc.printf("  returns %d\r\n", dataFromSlave);
        
        valueToSendToSlave++;
        
        wait(5); // Wait for 5 seconds for readability only
        
    }
}