SPRUJ79 November 2024 F29H850TU
Figure 41-4 shows typical connections of the SPI for communications between two controllers: a controller and a peripheral.
The controller transfers data by sending the SPICLK signal. For both the peripheral and the controller, data is shifted out of the shift registers on one edge of the SPICLK and latched into the shift register on the opposite SPICLK clock edge. If the CLK_PHASE bit is high, data is transmitted and received a half-cycle before the SPICLK transition. As a result, both controllers send and receive data simultaneously. The application software determines whether the data is meaningful or dummy data. There are three possible methods for data transmission:
The controller can initiate data transfer at any time because the controller controls the SPICLK signal. The software, however, determines how the controller detects when the peripheral is ready to broadcast data.
The SPI operates in controller or peripheral mode. The CONTROLLER_PERIPHERAL bit selects the operating mode and the source of the SPICLK signal.