SNIU028D February 2016 – September 2020 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
The Boot ROM supports a function to read a previously calculated checksum over a portion of the address space. The USB/PMBus adapter initiates a PMBus read block message to read a checksum calculation within the UCD3138. The PMBus master sends the device address, a command byte of 0xEE. The UCD3138 returns the four checksum bytes and a PEC byte. Upon detection of the command byte 0xEE, the Boot ROM reads the calculated checksum and returns to the PMBus master.
Start | Device Address & R/W (0x16) | Command Byte (0xEE) | Block Size (0x04) | Checksum[31:24] |
Checksum[23:16] | Checksum[15:8] | Checksum[7:0] | PEC | Stop |