R8C2G Datasheet, PDF (152/344 Pages) Renesas Technology Corp – MCU

R8C/2G Group
14. ID Code Areas
14. ID Code Areas
14.1 Overview
The ID code areas are used to implement a function that prevents the flash memory from being rewritten in
standard serial I/O mode. This function prevents the flash memory from read, rewritten, or erased.
The ID code areas are assigned to 0FFDFh, 0FFE3h, 0FFEBh, 0FFEFh, 0FFF3h, 0FFF7h, and 0FFFBh of the
respective vector highest-order addresses of the fixed vector table. Figure 14.1 shows the ID Code Areas.
ID code areas
Address
0FFDFh to 0FFDCh
0FFE3h to 0FFE0h
0FFE7h to 0FFE4h
0FFEBh to 0FFE8h
0FFEFh to 0FFECh
0FFF3h to 0FFF0h
0FFF7h to 0FFF4h
0FFFBh to 0FFF8h
0FFFFh to 0FFFCh
ID1
Undefined instruction vector
ID2
Overflow vector
BRK instruction vector
ID3
Address match vector
ID4
Single step vector
ID5
Watchdog timer/voltage monitor 1 and voltage
monitor 2/comparator 1 and comparator 2 vector
ID6
Address break vector
ID7
(Reserved)
OFS Reset vector
4 bytes
Figure 14.1 ID Code Areas
14.2 Functions
The ID code areas are used in standard serial I/O mode. Unless 3 bytes (addresses from 0FFFCh to 0FFFEh) of the
reset vector are set to FFFFFFh, the ID codes stored in the ID code areas and the ID codes sent from the serial
programmer or the on-chip debugging emulator are checked to see if they match. If the ID codes match, the
commands sent from the serial programmer or the on-chip debugging emulator are acknowledged. If the ID codes
do not match, the commands are not acknowledged. To use the serial programmer or the on-chip debugging
simulator, first write predetermined ID codes to the ID code areas.
As the ID code areas are allocated in the flash memory (not in the SFRs), they cannot be rewritten by executing an
instruction. Write appropriate values when creating a program.
Rev.1.00 Apr 04, 2008 Page 132 of 318
REJ09B0387-0100