SPRUIY4B February 2023 – May 2024 TMS320F2800152-Q1 , TMS320F2800153-Q1 , TMS320F2800154-Q1 , TMS320F2800155 , TMS320F2800155-Q1 , TMS320F2800156-Q1 , TMS320F2800157 , TMS320F2800157-Q1
The Read Byte and Read Word messages (Figure 20-19) consist of a device address, a command byte, received data bytes from a slave, and an optional PEC byte. Read Byte messages include a single byte, while the Read Word message protocol supports receipt of 2 bytes from the slave. Similar to the Receive Byte Protocol, the PMBMC register is configured to receive 1 or 2 bytes, the CMD_EN bit is set and the PEC_EN is configured to expect or not expect a PEC byte appended to the message. The PMBus module automatically terminates the message after the expected number of bytes is received from the slave or if the slave does not properly acknowledge any portion of the message.
In addition to programming the PMBMC register, the firmware is expected to load the command byte into bits 7-0 of the PMBTXBUF register. Any data received from the slave is found in the PMBRXBUF register.