The Write 16 Bytes message writes a block of 16 data bytes starting at a specified address. The Write 16 Bytes message utilizes the PMBus write block message format. The PMBus Master initiates the message by sending the device address, a command byte of 0xF4, a block length of 0x14, the 32-bit write address location, sixteen data bytes and a PEC byte. The Boot ROM interprets the command byte and stores the data bytes starting at the write address specified by the incoming message.
Start | Device Address & R/W (0x16) | Command Byte (0xF4) | Block Size (0x14) | Write Address[31:24] |
Write Address[24:16] | Write Address[15:8] | Write Address[7:0] | Data Byte[0] |
Data Byte[1] | Data Byte[2] | Data Byte[3] | Data Byte[4] |
Data Byte[5] | Data Byte[6] | Data Byte[7] | Data Byte[8] |
Data Byte[9] | Data Byte[10] | Data Byte[11] | Data Byte[12] |
Data Byte[13] | Data Byte[14] | Data Byte[15] | PEC | Stop |
The Write 16 Bytes message is normally very quick, and no PMBus delay is required. However, the Write 16 Bytes message can be used for writing to data and program flash, simply by writing to the appropriate address. In this case, 200 µsec should be allowed before starting the next message.