Datasheet

Section 22 Flash Memory
Page 1196 of 1408 R01UH0309EJ0500 Rev. 5.00
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
(12) User ROM Sum Check
The boot program will add all the data bytes in the user ROM area and return the result in
response to a user ROM sum check command.
Command H'4B
• Command, H'4B, (1 byte): Sum check for user ROM
Response H'5B Size Checksum of user ROM SUM
• Response, H'5B, (1 byte): Response to the user ROM sum check
• Size (1 byte): The number of bytes that represents the checksum
This is fixed to 4.
• Checksum of user ROM (4 bytes): Result of checksum calculation for the user ROM area; the
total of all the data in the ROM, in byte units.
• SUM (1 byte): Sum check for data being transmitted
(13) Data Flash Sum Check
The boot program will add all the data bytes in the data flash area and return the result in response
to a data flash sum check command.
Command H'61
• Command, H'61, (1 byte): Sum check for data flash
Response H'71 Size Checksum of data flash SUM
• Response, H'71, (1 byte): Response to the data flash sum check
• Size (1 byte): The number of bytes that represents the checksum
This is fixed to 4.
• Checksum of data flash (4 bytes): Result of checksum calculation for the data flash area; the
total of all the data in the data flash, in byte units.
• SUM (1 byte): Checksum value that makes the sum of the bytes from the command to the
SUM byte become H'00.
(14) User ROM Blank Check
The boot program will check to see if the whole user ROM area is blank and return the result in
response to a user ROM blank check command.
Command H'4D
• Command, H'4D, (1 byte): Blank check for user ROM