Boot Rom Execute Flash Command Byte, Valid Values - Texas Instruments UCD3138 Technical Reference Manual

Flash Functions
13.5.3 Execute Flash
The Boot ROM supports a function to exit the ROM code and start execution of code from the Program
Flash through a PMBus message. The PMBus Master initiates a PMBus Send Byte message to the
PMBus slave on the UCD3138. The master starts the message by sending the device address of 0xB, a
command byte of 0xF0 and a PEC byte. Upon receipt of the user-defined command byte of 0xF0, the
Boot ROM configures the memory selects for program flash operation and resets the program counter to
0. Following reconfiguration of the memory selects, the Program Flash now resides at address location 0
and code is now read from the flash instead of Boot ROM code.
Start Device Address & R/W
The Execute Flash command starts execution from Program Flash regardless of the state of the
checksums. When the processor starts executing from flash it is in supervisor mode and in ARM mode.
Normally the flash program will configure stack pointers and any processor registers in these modes and
then switch to Thumb mode and to User mode for efficiency and safety while executing the customer
program. See Section 14.1
For the other members of the UCD3138 family which have more than one block of program flash, there is
sometimes a second option to control which program flash block should be mapped to address 0. For this
second option, the command byte should be set to 0xF7. See
Table 13-3. Boot ROM Execute Flash Command Byte, Valid Values
UCD3138, UCD3138A
UCD3130A64,
UCD3138064A
UCD3138A64,
UCD3138A64A
UCD3138128,
UCD3138128A
(1)
Use the command byte to map different program flash blocks to address 0.
13.5.4 Flash Programming Sequence using Boot ROM
To program the flash, first send the appropriate Mass Erase commands. The Flash values will all become
0xFF. Then send a single Write 16 Bytes command for the start of each block of memory that needs to be
written. For the rest of the block, it is more efficient to send Write Next 16 Bytes commands. A system
which can translate a UCD3138 object file to PMBus commands is required. The Fusion Design GUI and
the UCD3138 Device GUI from Texas Instruments can both perform this download function when used
with the USB Interface Adapter and a PC. Production portable programmers will be made available from
3rd parties. Please contact TI for further guidance.
To verify the flash programming, there are three options:
1. Read the flash back with a combination of Configure Read Address, Read 16 Bytes, and Read Next 16
Bytes commands
2. If the checksum is programmed, simply reset the device and verify that it executes the Flash Memory.
This works only for Program Flash. Often the program in flash verifies a checksum for data flash
3. Use the checksum functions below to have the device calculate a checksum of the flash and compare
it to the expected value.
446
Boot ROM and Boot Flash
Command Byte (0xF0)
(0x16)
for more information on processor modes.
Command Byte = 0xF0
pflash: 0x0000 to 0x7FFF
pflash block 1: 0x0000 to 0x7FFF
pflash block 2: 0x8000 to 0xFFFF
pflash block 0: 0x0000 to 0x7FFF
pflash block 1: 0x8000 to 0xFFFF
pflash block 0: 0x00000 to 0x07FFF
pflash block 1: 0x08000 to 0x0FFFF
pflash block 2: 0x10000 to 0x17FFF
pflash block 3: 0x18000 to 0x17FFF
Copyright © 2016, Texas Instruments Incorporated
PEC
Table 13-3 for more details.
Command Byte = 0xF7
not valid
pflash block 1: 0x8000 to 0xFFFF
pflash block 2: 0x0000 to 0x7FFF
not valid
pflash block 0: 0x10000 to 0x17FFF
pflash block 1: 0x18000 to 0x17FFF
pflash block 2: 0x00000 to 0x07FFF
pflash block 3: 0x08000 to 0x0FFFF
SNIU028A – February 2016 – Revised April 2016
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