Example description
This example describes how to use SPI in POLLING or INTERRUPT mode.
The LOOPBACK_TEST macro is used to enable Loop-back mode of SPI peripheral. It allows a simple software testing. The transmit and receive data is connected together. No more connection is required in this case.
If LOOPBACK_TEST macro is disabled, it is needed to connect 2 hardware boards, one for Master and one for Slave.
SPI configuration:

CPHA = 0: Data is sampled on the first clock edge of SCK.
CPOL = 0: The rest state of the clock (between frames) is low.
Sample rate = 100KHz.
DSS = 8: 8 bits per transfer.
After initialize transmit buffer, SPI master/slave will transfer a number of bytes to SPI slave/master and receive data concurrently.
After a transfer completed, receive and transmit buffer will be compared. If the receive buffer is matched with transmit buffer, the Blue led blinks. If not the Red led blinks. This example supports 2 transfer modes: POLLING mode and INTERRUPT mode.

Configure hardware, connect master board and slave board as below
Update SPI_MODE_TEST macro for the relevant board, Build and Program Internal Flash.
Reset the slave board and then master board. Observe the LED on board.

Special connection requirements
Hardware configuration

SPI pins:
P0.12: SPI_SCK
P0.13: SPI_SSEL
- P0.6: SPI_MISO
  - P0.14: SPI_MOSI
    The SCK pin of master board is connected to SCK of slave board.
    The SSEL pin of master board is connected to SSEL of slave board.
    The MISO pin of master board is connected to MISO of slave board.
    The MOSI pin of master board is connected to MOSI of slave board.
    Common ground must be connected together between two boards.

Build procedures:
LPC8xx example quickstart for IAR EWARM
LPC8xx example quickstart for Keil uVision4
LPC8xx example quickstart for Code Red Xpresso

Supported boards and board setup:
NXP Xpresso LPC812 board

Submitting LPCOpen issues:
Community support for LPCOpen