Renesas M16C/64A Series User Manual page 724

M16C/64A Group
30.9.2 Forced Erase Function
Use the forced erase function in standard serial I/O mode. When the reserved word, "ALeRASE" in
ASCII code, is sent from the serial programmer as an ID code, the contents of program ROM 1 and
program ROM 2 will all be erased. However, if the ID codes stored in the ID code storage addresses
are set to a reserved word other than "ALeRASE" (other than the combination table listed in Table
30.19), the ROMCR bit in the OFS1 address is 1 (ROMCP1 bit enabled), and the ROMCP1 bit in the
OFS1 address is 0 (ROM code protect enabled), the forced erase function is ignored and ID code
check is executed by the ID code check function. Table 30.20 lists conditions and functions for forced
erase function.
When both the ID codes sent from the serial programmer and the ID codes stored in the ID code
storage addresses correspond to the reserved word "ALeRASE", program ROM 1 and program ROM 2
will be erased. However, when the serial programmer sends other than "ALeRASE", even if the ID
codes stored in the ID code storage addresses are "ALeRASE", there is no ID match and no command
is accepted. The flash memory cannot be operated.
Table 30.20 Forced Erase Function
ID code from serial
programmer
ALeRASE
Other than
ALeRASE
Note:
1. When the combination of the stored addresses is "Protect", refer to 30.9.3 "Standard Serial I/O
Mode Disable Function".
30.9.3 Standard Serial I/O Mode Disable Function
Use the standard serial I/O mode disable function in standard serial I/O mode. When the ID codes in
the ID code stored addresses are set to "Protect" in ASCII code (see Table 30.19 "Reserved Word of ID
Code"), the MCU does not communicate with the serial programmer. Therefore, the flash memory
cannot be read, written or erased by the serial programmer. User boot mode can be selected even
when the ID codes are set to "Protect".
When the ID codes are set to "Protect", the ROMCR bit in the OFS1 address is 1 (ROMCP1 bit
enabled), and the ROMCP1 bit in the OFS1 address is set to 0 (ROM code protect enabled), ROM
code protection cannot be disabled by the serial programmer. Therefore, the flash memory cannot be
read, written, or erased by the serial or parallel programmer.
R01UH0136EJ0210 Rev.2.10
Jul 31, 2012
Condition
Code in ID code ROMCP1 bit in the
storage address OFS1 address
ALeRASE
1 (ROM code
Other than protect disabled)
(1)
ALeRASE 0 (ROM code
protect enabled)
ALeRASE
Other than
(1)
ALeRASE
–
Program ROM 1 and program ROM 2
all erase (forced erase function)
ID code check (ID code check function)
ID code check (ID code check function.
–
– ID code check (ID code check function)
30. Flash Memory
Function
No ID match)
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