SWRU543B January 2019 – June 2025 CC3230S , CC3230SF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
This chapter is intended to provide programmers with a functional presentation of the master and slave serial peripheral interface module, and provides a module configuration example. The serial peripheral interface (SPI) is a 4-wire bidirectional communications interface that converts data from parallel to serial.
The CC32xx device has two SPI interfaces:
This chapter focuses on the second SPI.
The SPI module performs serial-to-parallel conversion on data received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral device. The SPI module can be configured as either a master or slave device. As a slave device, the SPI module can also be configured to disable its output, which allows a master device to be coupled with multiple slave devices. The TX and RX paths are buffered with separate internal FIFOs. The SPI module also includes a programmable bit rate clock divider to generate the output serial clock derived from the input clock of the SPI module. Bit rates are generated based on the input clock, and the maximum bit rate is determined by the connected peripheral.
The SPI allows full duplex between a local host and SPI-compliant external devices (slaves and masters). Figure 8-1 shows a high-level overview of the SPI system.
Figure 8-1 SPI Block Diagram