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22.
Flash Memory Operation
22.3
How to Reprogram Flash using Single Boot Mode
(2)
22.3.5.4
two's complement of the total sum. The controller must perform the same checksum operation in transmit-
ting checksum bytes.
2019-02-06
Start
Are all bytes the
same?
Are all bytes
equal to FFH?
Password area error
Figure 22-11 Password area check flowchart
Password verification to Flash memory chip erase and protect bit erase command
When a password is enable in the erase password necessity determination area as shown in Fig-
ure 22-12 and the passwords are identical data, a password area error occurs. If a password area er-
ror is determined, an ACK response to the 17th byte of CHECK SUM sends 0x41 regardless of the
password verification.
The boot program verifies 5th byte to 16th byte of receive data (password data). A password er-
ror occurs if all 12 bytes do not match. If the password error is determined, an ACK response data
to the 17th of CHECK SUM data is a password error.
The password verification is performed even if the security function is enabled.
Start
Need password ?
Are all bytes the
same?
YES
Password area error
Figure 22-12 Password area check flowchart
CHECK SUM Calculation
The checksum is calculated by 8-bit addition to transmit data, dropping the carries, and taking the
Example of CHECK SUM
YES
YES
Password area is normal.
YES
Password area is normal.
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TMPM3V6/M3V4
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