tmp89fm42 TOSHIBA Semiconductor CORPORATION, tmp89fm42 Datasheet - Page 367

• Manufacturer Part Number: tmp89fm42
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

RA002
22.10Checksum (SUM)
22.10.1Calculation method
22.10.2Calculation data
Table 22-19 Data for which a Checksum Is Calculated
Flash memory erase command
Flash memory write command
Flash memory SUM output com-
mand
Flash memory read command
RAM loader command
Product ID code output command
Flash memory status output com-
mand
mand execution:
For the following operation commands, a checksum is returned to verify the appropriateness of the result of com-
Operation command
- Flash memory erase command (0xF0)
- Flash memory write command (0x30)
- Flash memory SUM output command (0x30)
- Flash memory read command (0x40)
- RAM loader command (0x60)
- Product ID code output command (0xC0)
- Flash memory status output command (0xC3)
The data is read in single-byte units, and the calculated result is returned as a word.
different calculation method is used. For more information, refer to Table 22-19.
The checksum (SUM) is calculated with the sum of all bytes, and the obtained result is returned as a word.
Example:
In the case of the product ID code output command and flash memory status output command, however, a
Table 22-19 shows the data for which a checksum is calculated for each command.
All data in the erased area of flash mem-
ory (whole or part of flash memory)
Data in the entire area of flash memory
Data in the read area of flash memory
RAM data written in the first received
RAM address through the last received
RAM address
9th through 18th bytes of transferred data
9th through 12th bytes of transferred data
0xA1
0xB2
0xC3
0xD4
Calculation data
If the data to be calculated consists of four bytes as shown
on the left, the checksum of the data is as follows:
0xA1 + 0xB2 + 0xC3 + 0xD4 = 0x02EA
SUM (HIGH)= 0x02
SUM (LOW)= 0xEA
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When the sector erase is executed, only the erased area is
used to calculate the checksum. In the case of the chip erase,
an entire area of the flash memory is used.
Even if a part of the flash memory is written, the checksum of
the entire flash memory area (0x8000 to 0xFFFF) is calcu-
lated. The data length, address, record type and checksum in
Intel Hex format are not included in the checksum.
The length of data, address, record type and checksum in Intel
Hex format are not included in the checksum.
For details, refer to "22.8.6 Product ID code output command
(operation command: 0xC0)".
For details, refer to Table "Table 22-14 Flash Memory Status
Output Commands".
Description
TMP89FM42