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# 1.27 SPI Interrupt

This example shows how to use the SPI peripheral to transmit and receive a block of data using interrupts.

## Description

This example demonstrates transmit and receive operation over SPI interface in a non-blocking manner using interrupts. It transmits known values from an array and verifies the data received through loop back by comparing both. The example application performs the loop back test only once after a power on reset. After the loop back is complete, the status of the loop back is indicated and the application remains idle. The loop back test requires the MOSI output pin to be connected to the MISO input pin so that anything transmitted will also be received.

## 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/spi/spi_self_loopback_blocking/firmware.

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

Project Name | Description
--- | ---
sam_e70_xult.X | MPLABX project for SAM E70 Xplained Ultra Evaluation Kit
sam_v71_xult.X | MPLABX project for SAM V71 Xplained Ultra Evaluation Kit

## Setting Up the Hardware

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

Project Name | Description
--- | ---
sam_e70_xult.X | SAM E70 Xplained Ultra Evaluation Kit
sam_v71_xult.X | SAM V71 Xplained Ultra Evaluation Kit

### Setting Up SAM E70 Xplained Ultra Evaluation Kit

- Use a jumper wire to short pin 16 and pin 17 of the EXT1 header
- Connect the Debug USB port on the board to the computer using a micro USB cable

### Setting Up SAM V71 Xplained Ultra Evaluation Kit

- Use a jumper wire to short pin 16 and pin 17 of the EXT1 header
- Connect the Debug USB port on the board to the computer using a micro USB cable

## Running the Application

1. Build and Program the application project using its IDE
2. LED indicates the success or failure:
   - The LED is turned ON when the value received matched with the transmitted value
   - The LED is turned OFF when the value received did not match with the transmitted value

The following table provides the LED names:

Board | LED Name
--- | ---
SAM E70 Xplained Ultra Evaluation Kit | LED1
SAM V71 Xplained Ultra Evaluation Kit | LED0