File content as of revision 4:8e18509be6ff:

#include "mbed.h"
#include "SimpleDMA.h"
#include "dmaSPIslave.h"


    #define PAYLOAD_LENGTH 16
    #define PAY_SPI_MOSI PTD6
    #define PAY_SPI_MISO PTD7
    #define PAY_SPI_CLK PTD5
    #define PAY_SPI_CS PTE16
    
   // dmaSPISlave spi(PAY_SPI_MOSI, PAY_SPI_MISO, PAY_SPI_CLK, PAY_SPI_CS);

dmaSPISlave spi(PTD6, PTD7, PTD5,PTD4 ); 
RawSerial pc(USBTX, USBRX);
//DigitalOut ledg(LED_GREEN);

bool flag = false;

void do_this(void){
    flag = true;
}

int main(){
    pc.baud(9600);
    pc.printf("inside main\r\n");
    spi.format(8,0);
    spi.frequency(10000000);
    
    uint8_t buffer[PAYLOAD_LENGTH] = {0};
    pc.printf("welcome to dma test, start sending data now\r\n");

//    initialise the buffer for dma
    spi.bulkRead_init(buffer, PAYLOAD_LENGTH, &do_this);
//    start dma read
    spi.bulkRead_start();
    
    while(true){
        if(flag){
            flag = false;
            //ledg = !ledg;
            

            for(int i = 0 ; i < PAYLOAD_LENGTH ; ++i){
                pc.printf("data %d   %d  \r\n",i, buffer[i]);            }
          pc.printf("\r\n");

            //start dma again after handling the data
            spi.bulkRead_start();
        }
    }
    
}