SPI Sample Application

This example demonstrates the usage of the SPI API by monitoring the communication with a slave device. The application allows reading, writing and transferring data to the slave device.

Demo requirements

To run this example you need:

• A compatible development board to host the application.
• A USB connection between the board and the host PC in order to transfer and launch the application.
• An external SPI device is required to run this example. Another possibility is to short MISO and MOSI lines of the SPI interface so what is written in the SPI interface (MOSI line) is read (MISO line).

Demo setup

Make sure the hardware is set up correctly:

1. The development board is powered on.
2. The board is connected directly to the PC by the micro USB cable.
3. If MISO and MOSI lines of the SPI interface are not shorted, an external SPI device must be connected to this interface.

Demo run

The example is already configured, so all you need to do is to build and launch the project.

Once application starts, configure all the SPI parameters (at the beginning they are all set to their default values):

• SPI interface: All the possible interface and device combinations are listed to choose one. Changing this option during normal operation resets all the other parameters to their default values.
• Clock polarity and phase: Each of them can be set to 0 or 1 according to SPI standard definition.
• Chip select: Select the behaviour of the Chip select pin (or SS Slave Select) They are all individually selectable according to SPI standard definition. They might not be supported. If that is the case, the mode is discarded and the console displays a message.
• Bit order: The order in which the bits are transmitted and received.
• Word length: The size of each transfer word. Possible values are 7, 8, or 16.
• Clock frequency: The maximum transfer speed in Hz.
• Read length: The amount of transfer words to receive during read process.

The application shows two fields named Data to send and Received data that correspond to the data to send to the slave device and the data received from it, respectively. Three buttons take control of these operations:

• Read data button: Reads from the slave device the amount of words specified by the Read length parameter and shows them in the Received data field. If no data has been read, this field is empty. In case of error, the console displays a message.
• Transfer data button: Writes in the slave device the data introduced in the Data to send field while, at the same time, reads from the slave device data with the same length as the written data. If no data has been read, this field is empty. In case of error, the console displays a message.
• Write data button: Writes in the slave device the data introduced in the Data to send field. In case of error, the console displays a message.

Compatible with

• ConnectCore 6 SBC
• ConnectCore 6 SBC v3
• ConnectCore 8X SBC Pro

License

Copyright (c) 2014-2025, Digi International Inc. support@digi.com

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.