Password String; Handling Of Password Error; Password Management During Program Development - Philips CEM2100/00 Service Manual

RXD pin
UART
Example
PNSA = F012H
PCSA = F107H
Password string = 01H,02H,03H,04H,05H

20.10.1Password String

The password string transmitted from the external controller is compared with the specified data in the flash
memory. When the password string is not matched to the data in the flash memory, the device enters the halt
condition due to the password error.

20.10.2Handling of Password Error

If a password error occurs, the device enters the halt condition. In this case, reset the device to reactivate the
serial PROM mode.

20.10.3Password Management during Program Development

If a program is modified many times in the development stage, confusion may arise as to the password.
Therefore, it is recommended to use a fixed password in the program development stage.
Example :Specify PNSA to F000H, and the password string to 8 bytes from address F001H
(PCSA becomes F001H.)
Password Section code abs = 0F000H
F0H 12H F1H 07H 01H 02H 03H 04H 05H 06H 07H 08H
PNSA PCSA
F012H
F107H
F108H
F109H
F10AH
F10BH
F10CH
F10DH
F10EH
06H,07H,08H
Figure 20-5 Password Comparison
DB 08H
DB "CODE1234"
Page 257
Password string
Flash memory
08H
"08H" becomes
the umber of
01H passwords
02H
03H
04H
8 bytes
05H
06H
07H
08H
: PNSA definition
: Password string definition
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