CMS32L051 User Manual |Chapter 13 Serial Interface SPI
www.mcu.com.cn 465 / 703
13.3.6 SPI pin port function control register
When using SPI, the control registers (port mode registers (PMxx, PMCxx) of the port function that are
multiplexed with the SPI input and output pins must be set. For details, please refer to 2.3.1 Port Mode
Register (PMxx)
When using the SPI pin multiplexed port as an output of SCK/SO/MO, you must set bit "0" to the port
mode register (PMxx, PMCxx) corresponding to each port. When the multiplexed port of SPI pin is used as the
input of SCK/SI/MI, the bit "1" of the Port Mode Register (PMxx) and the bit "0" of PMCxx must be set for each
port. In this case, the bit of the port register (Pxx) can be "0" or "1". For details, refer to "2.5 Register Settings
when Using Multiplexing Function".