SPI application (app/spi-app.c)

Table of Contents

• Jetson TX2
• Jetson AGX

SPI application demonstrates how to access/manipulate Always On (AON) SPI from the SPE/AON processor. SPI 2 is in AON domain for both Jetson TX2 and Jetson AGX. The compilation of this demo app can be controlled by "ENABLE_SPI_APP" flag in the soc/*/target_specific.mk file. The app uses loop back test, user must short MISO and MOSI signals (follow below sections for pin map) in order to successfully run this app. The app sends predefined bytes and compares sent bytes with received, on success it should print "SPI test successful".

Note

It is required to compile device tree and flash board to have device tree updated after making kernel device tree changes as described in following sections.

Jetson TX2

SPI 2 signals are available at connector J23 with below pin mappings.

• Pin 38 - CLK
• Pin 40 - MISO
• Pin 42 - MOSI
• Pin 44 - CS0

SPI 2 is also enabled and accessed in tegra186-display-e3320-1000-a00.dtsi device tree file from kernel side which needs to be disabled as shown in below code snippet.

spi@c260000 {
        status = "disabled";
        spi-max-frequency = <12000000>;
        ...
}

Jetson AGX

SPI 2 signals are available at connector J6 with below pin mappings.

• Pin A5 - CLK
• Pin A6 - MISO
• Pin A7 - MOSI
• Pin A8 - CS0

SPI 2 is also enabled and accessed in tegra194-camera-e3377-a00.dtsi device tree file from kernel side which needs to be disabled as shown in below code snippet.

spi@c260000 {
        status = "disabled";
        spi-max-frequency = <12000000>;
        ...
}