1.13 SPI Driver Asynchronous - Self Loopback Multi Client

This example demonstrates how to use the SPI driver in asynchronous mode to achieve self-loop back between multiple clients.

Description

  • This example writes and reads back the same data (self loop back) for two different clients connected over the same SPI bus by using the multi client feature of the driver
  • It uses the request (write and read request) queuing feature of the asynchronous driver and does not waste CPU bandwidth in waiting for previous request completion
  • The example also demonstrates how to setup two different client transfers at different baud rates
  • This example performs self loop back only once after a power on reset
  • Success is indicated when a successful self loop back is reported by both the clients
  • After the loop back test is complete, the application remains in the idle state

Downloading and Building the Application

To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.

Path of the application within the repository is apps/driver/spi/async/spi_self_loopback_multi_client/firmware.

To build the application, refer to the following table and open the project using its IDE.

Project NameDescription
sam_9x60_curiosity.XMPLABX project for SAM9X60-Curiosity board
sam_9x60_curiosity_freertos.XMPLABX project for SAM9X60-Curiosity board

Setting Up AT91Bootstrap loader

To load the application binary onto the target device, we need to use at91bootstrap loader. Refer to the at91bootstrap loader documentation for details on how to use it to bootstrap the application binaries.

Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project NameDescription
sam_9x60_curiosity.X

sam_9x60_curiosity_freertos.X

SAM9X60-Curiosity board

Setting Up SAM9X60-Curiosity Board

  • Use jumper wire to Connect “MOSI Pin of mikroBUS Connector” to “MISO Pin of mikroBUS Connector”
    • FLEXCOM5 MOSI signal is mapped to PA22 that is routed to “MOSI Pin of mikroBUS Connector”
    • FLEXCOM5 MISO signal is mapped to PA21 that is routed to “MISO Pin of mikroBUS Connector”
  • Connect the USB port J1 on board to the computer using a micro USB cable (to power the board)
  • Connect the JTAG J12 on board to the computer using a JTAG based debugger

Running the Application

  1. Build and program the application using its IDE
  2. LED is turned ON on Success
Refer to the following table for LED name:
BoardLED Name
SAM9X60-Curiosity boardRGB_LED (Green)