R8C/18 Group, R8C/19 Group
17. Flash Memory Version
Rev.1.30
Apr 14, 2006
Page 176 of 233
REJ09B0222-0130
17.3
Functions to Prevent Rewriting of Flash Memory
Standard serial I/O mode has an ID code check function, and parallel I/O mode has a ROM code protect
function to prevent the flash memory from being read or rewritten easily.
17.3.1
ID Code Check Function
This function is used in standard serial I/O mode. Unless the flash memory is blank, the ID codes sent
from the programmer and the ID codes written in the flash memory are checked to see if they match.
If the ID codes do not match, the commands sent from the programmer are not acknowledged. The
ID codes consist of 8 bits of data each, the areas of which, beginning with the first byte, are 00FFDFh,
00FFE3h, 00FFEBh, 00FFEFh, 00FFF3h, 00FFF7h, and 00FFFBh. Write programs in which the ID
codes are set at these addresses and write them to the flash memory.
Figure 17.3
Address for Stored ID Code
4 bytes
Address
00FFDFh to 00FFDCh
Undefined instruction vector
NOTE:
1. The OFS register is assigned to 00FFFFh. Refer to
Figure 13.2 Registers
OFS and WDC
and
Figure
13.3 Registers
WDTR and WDTS
for OFS register
details.
Overflow vector
00FFE3h to 00FFE0h
00FFE7h to 00FFE4h
BRK instruction vector
Address match vector
00FFEBh to 00FFE8h
00FFEFh to 00FFECh
Oscillation stop detection/watchdog
timer/voltage monitor 2 vector
00FFF3h to 00FFF0h
00FFF7h to 00FFF4h
Address break
00FFFBh to 00FFF8h
Reset vector
00FFFFh to 00FFFCh
(Reserved)
ID1
ID2
ID3
ID4
ID5
ID6
ID7
(Note 1)
Single step vector
