1.11 SDMMC Driver Asynchronous - SDMMC Read Write

This example application shows how to use the SDMMC driver in asynchronous mode to perform block operations on the SD Card Media.

Description

This example uses the SDMMC driver in asynchronous mode in both Bare-Metal and RTOS environment to perform Block Erase/Write/Read operations on SD-Card
This application writes 60KB (61440 bytes) of data starting at the SD Card memory location 0x2000
It then reads and verifies the written data

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/sdmmc/async/sdmmc_read_write/firmware.

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


Project Name	Description
sam_9x60_curiosity.X	MPLABX project for SAM9X60-Curiosity board
sam_9x60_curiosity_freertos.X	MPLABX 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 Name	Description
sam_9x60_curiosity.X sam_9x60_curiosity_freertos.X	SAM9X60-Curiosity board

Setting Up SAM9X60-Curiosity Board

Insert the SD card into SDMMC0 (J3) slot on the board
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

Build and program the application using its IDE
The LED is turned ON when the read data from the SD Card matches with the written data

Note: This demo application performs a raw read-write operation on the SD card. This causes the partition information to be overwritten causing the SD card file system to be corrupted. Hence resetting the board will not re-run the application demo (Board will fail to boot since it cannot find a valid partition). To repeat the demo we need to reformat SD card and prepare it as defined by the hardware setup.

Refer to the following table for LED name:


Board	LED Name
SAM9X60-Curiosity board	RGB_LED (Green)