M16C30P_07 Datasheet, PDF (247/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
20. One Time Flash Version
20.2 Functions to Prevent One Time Flash Version from Being Read
Parallel I/O mode of one time flash has a ROM code protect function, and Standard I/O mode of one time flash has
an ID code check function.
20.2.1 ROM Code Protect Function
The ROM code protect function prevents the one time flash being read in parallel I/O mode. The ROM code
protect function is enabled when the address 0FFFFFh is set to "3Fh". The ROM code protect function is
disabled when the address 0FFFFFh is set to "00h" or "FFh". Write a program with "3Fh", "00h" or "FFh" set
in the address to one time flash version.
Table 20.3 lists the values and functions of the address 0FFFFFh.
Table 20.3 The Values and Functions of Address 0FFFFFh
Set Value
3Fh
00h
FFh
Other than the above
Function
ROM code protect enabled
ROM code protect disabled
Do not set.
20.2.2 ID Code Check Function
The ID code check function is used in standard serial I/O mode. The ID code sent from the serial programmer
and the ID code written in the one time flash memory are checked to see if they match. If these ID codes do not
match, the commands sent from the serial programmer are not acknowledged. However, if the four bytes of the
reset vector are FFFFFFFFh, the ID code is not checked and all commands can be acknowledged.
The ID codes is 7-byte data stored consecutively, beginning with the first byte, into addresses 0FFFDFh,
0FFFE3h, 0FFFEBh, 0FFFEFh, 0FFFF3h, 0FFFF7h, and 0FFFFBh. Write a programs with the ID codes set at
these addresses to the one time flash memory.
Address
0FFFDFh to 0FFFDCh
0FFFE3h to 0FFFE0h
0FFFE7h to 0FFFE4h
0FFFEBh to 0FFFE8h
0FFFEFh to 0FFFECh
0FFFF3h to 0FFFF0h
0FFFF7h to 0FFFF4h
0FFFFBh to 0FFFF8h
0FFFFFh to 0FFFFCh
ID1
ID2
ID3
ID4
ID5
ID6
ID7
“3Fh” ⁽¹⁾
Undefined instruction vector
Overflow vector
BRK instruction vector
Address match vector
Single step vector
Watchdog timer vector
DBC vector
NMI vector
Reset vector
Figure 20.3
4 bytes
Note1: The ROM code protect function is enabled when it is set to "3Fh".
Address for ID Code Stored in One Time Flash Version
Rev.1.22 Mar 29, 2007 Page 231 of 291
REJ09B0179-0122