SPI Example

Purpose

This example uses Serial Peripheral Interface (SPI) of one EK board in slave mode to communicate with another EK board's SPI in master mode.

Requirements

This package can be used with two SAM evaluation kits boards. Please connect the SPI pins from one board to another.

• SAM4L8 Xplained Pro board – SAM4L8 Xplained Pro board
• VCC – VCC
• NPCS0(PC03,EXT1/PIN15) – NPCS0(PC03,EXT1/PIN15)
• MISO(PA21,EXT1/PIN17) – MISO(PA21,EXT1/PIN17)
• MOSI(PA22,EXT1/PIN16) – MOSI(PA22,EXT1/PIN16)
• SPCK(PC30,EXT1/PIN18) – SPCK(PC30,EXT1/PIN18)

• GND – GND

  Descriptions

  This example shows control of the SPI, and how to configure and transfer data with SPI. By default, example runs in SPI slave mode, waiting SPI slave & UART inputs.

  The code can be roughly broken down as follows:

  • 't' will start SPI transfer test.
    1. Configure SPI as master, and set up SPI clock.
    2. Send 4-byte CMD_TEST to indicate the start of test.
    3. Send several 64-byte blocks, and after transmitting the next block, the content of the last block is returned and checked.
    4. Send CMD_STATUS command and wait for the status reports from slave.
    5. Send CMD_END command to indicate the end of test.
  • Setup SPI clock for master.

  Usage

  1. Compile the application.
  2. Connect the UART port of the evaluation board to the computer and open it in a terminal.
     • Settings: 115200 bauds, 8 bits, 1 stop bit, no parity, no flow control.
  3. Download the program into the evaluation board and run it.
  4. Upon startup, the application will output the following line on the terminal:

     -- Spi Example  --
     -- xxxxxx-xx
     -- Compiled: xxx xx xxxx xx:xx:xx --

  5. The following traces detail operations on the SPI example, displaying success or error messages depending on the results of the commands.