SLAU923B June 2025 – April 2026 MSPM0H3215 , MSPM0H3216 , MSPM0H3216-Q1
When using the Motorola frame format, the CDMODE bit can be set to use the CS3/CD line as signal to distinguish between Command and Data information. This is often used for LCD or data storage devices.
Command Function: To send out COMMAND, load CDMODE with 0xF and populate the transmit FIFO with the COMMAND data to be sent; the module will drive CS3/CD low and transmit the COMMAND data on the TX line.
Data Function with CDMODE as counter: After the COMMAND data is sent, load CDMODE with the number of data bytes to be transmitted and populate the transmit FIFO with the data to be sent. CS3/CD line will be driven high & data will be transmitted on the TX line; CDMODE will be decremented by 1 after each transmission. CS3/CD line remains high after the counter reaches '0'.
Alternatively, the DATA function can also be implemented in MANUAL mode, by writing CDMODE with a value of '0' and then populating the transmit FIFO. This will pull CS3/CD high and transmit populated in the transmit FIFO.