This subsystem demonstrates how to use MSPM0 to achieve IO expander function through the communication command from serial peripheral interface (SPI), I2C, or universal asynchronous receiver-transmitter (UART) by the host. This expansion is helpful when the number of GPIOs on the host is inadequate. In addition to supporting control of the GPIO output, the subsystem can also read back the GPIO status through SPI, I2C, or UART. Figure 1-1 shows the basic architecture of the subsystem and the modules which are used in this case.

Figure 1-1 Subsystem Functional Block Diagram

Table 1-2 has links to the example code. In this demonstration, the IO control number is limited to eight. However, users can do further IO expansion by referring to this demonstration.

Table 2-1 shows the required peripherals and function modules in this application.

This example is compatible with the devices in Table 1-2. The corresponding EVM can be used for prototyping.