SPRUIZ1B July 2023 – August 2024 TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DH-Q1 , TMS320F28P659DK-Q1 , TMS320F28P659SH-Q1
The Read Byte and Read Word messages (Figure 29-6) consist of a device address, a command byte, received data bytes from a target, 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 target. Similar to the Receive Byte Protocol, the PMBCCR 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 target or if the target does not properly acknowledge any portion of the message.
In addition to programming the PMBCCR register, the firmware is expected to load the command byte into bits 7-0 of the PMBTXBUF register. Any data received from the target is found in the PMBRXBUF register.