This subsystem serves as a SPI-to-I2C bridge. In this subsystem, the MSPM0 device is the SPI Peripheral and I2C Controller. When a SPI controller transmits to the bridge SPI peripheral, the peripheral collects all the received data. Once the peripheral reaches the expected maximum message, the peripheral transmits the data using the I2C controller. The device sends an I2C transmit request and waits for I2C data from the I2C target. When the I2C controller finishes reading the data, the bridge waits for a SPI controller to send a request to read the data from the bridge. Finally, the bridge transmits the I2C controller received data through the bridge SPI peripheral.

Figure 1-1 System Functional Block Diagram

Two MSPM0 peripherals are used for this subsystem: the SPI and I2C.

1. The subsystem project can be found in the M0 SDK under MSP Subsystems folder.
2. Set up the I2C module in SysConfig. Set the device in Controller Mode and leave the rest of the settings by default. Now navigate to the Interrupt configuration tab and enable the TX Done and RX_FIFO_TRIGGER interrupts.
3. Set up the SPI module in SysConfig. Put the device in SPI Peripheral mode and leave the rest of the settings on default. Now, navigate to the Interrupt configuration tab and enable the Receive and Transmit interrupts.
4. Define the maximum packet size to the desired package size.