Write Next 16 Bytes - Texas Instruments UCD3138 Technical Reference Manual

Memory Write Functionality
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.

13.4.3 Write Next 16 Bytes

The Write Next 16 Bytes message writes a block of 16 data bytes starting at the last programmed write
address incremented by 16. It is designed to improve efficiency when many sequential blocks are being
written. The Write Next 16 Bytes message utilizes the PMBus write block message format. Use of the
Write Next 16 Bytes message assumes the write address was set previously with a Write Block message.
The PMBus Master initiates the message by sending the device address, a command byte of 0xF3, a
block length of 0x10, sixteen data bytes and a PEC byte. The Boot ROM interprets the command byte and
stores the data bytes starting at the write address, calculated from the previously set address incremented
by 16.
Start Device Address & R/W
Data Byte[1]
Data Byte[5]
Data Byte[9]
Data Byte[13]
The Write Next 16 Bytes message is normally very quick, and no PMBus delay is required. However, the
Write Next 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.
13.5 Flash Functions
In addition to the ability to read and write internal memory map locations, the UCD3138 Boot ROM
supports flash functions. These functions allow the user to perform a mass erase or page erase of either
the Program Flash or Data Flash. The Boot ROM also supports a PMBus command byte that initiates
execution of code from the Program Flash, starting at address 0.
13.5.1 Mass Erase
Start Device Address &
R/W (0x16)
The Boot ROM supports the initiation of a mass erase of either the Program or Data Flash through a
PMBus message. The PMBus Master initiates a PMBus write byte message to the UCD3138. The master
initiates the message by sending the device address, a command byte of 0xF2, a single data byte and the
PEC byte. The data byte identifies which flash memory will be mass erased. A value of 0x0 indicates a
mass erase of the Data Flash, while a value of 0x1 indicates a mass erase of the Program Flash. Upon
receipt of the mass erase message, the Boot ROM sets the appropriate control bit to initiate a mass erase
of the flash memory. The flash control logic generates the sequencing of control signals to perform a mass
erase operation on the memory. Mass erase takes approximately 20 msec. The PMBus Master should
wait at least 20 msec after sending this command before attempting any other PMBus communication. For
the other members of the UCD3138 family, the "data byte" parameter can have different values,
depending on which program flash block you wish to erase. See
444
Boot ROM and Boot Flash
Command Byte (0xF3)
(0x16)
Data Byte[2]
Data Byte[6]
Data Byte[10]
Data Byte[14] Data Byte[15]
Command Byte
(0xF2)
Copyright © 2016, Texas Instruments Incorporated
Block Size (0x10)
Data Byte[3]
Data Byte[7]
Data Byte[11]
PEC
Data Byte (0/1) PEC
Table 13-2 for more details.
SNIU028A – February 2016 – Revised April 2016
www.ti.com
Data Byte[0]
Data Byte[4]
Data Byte[8]
Data Byte[12]
Stop
Stop
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