In this code example, we make PIC24FJ128GA010 on Explorer 16 Development Board as an SPI Master to communicate with PIC24FJ64GA002 on 16-Bit 28-Pin Demo Board.

The code does the following operations on SPI slave,
(1) write four bytes to slave;
(2) read four bytes from slave simultaneously;
(3) blinding the LED after finish every times.

Master: [1st byte to slave]   [2nd byte to slave]  [3rd byte to slave]  [hash byte to read back]
Slave:  [hash byte in buffer] [1st byte to master] [2nd byte to master] [3rd byte to master]