39. ROM (Flash Memory for Code Storage)
39.11 ID Code Protection on Connection of the On-Chip Debugger
This function is used to prohibit connection with the on-chip debugger. When connecting an on-chip debugger, the
control code and ID code that have been written to the ROM are used to determine whether ID code protection on
connection of the on-chip debugger is enabled or disabled and to judge ID code protection on connection of the on-chip
debugger. When the ID code protection is enabled, the code sent from the on-chip debugger is compared with the control
code and ID code in the ROM to determine whether they match. If they match, connection with the on-chip debugger is
allowed. If they do not match, the on-chip debugger cannot be connected. However, if the control code is 52h and the ID
code is 50h, 72h, 6Fh, 74h, 65h, 63h, 74h, FFh, ..., FFh (from the ID code 1 field), there is no determination of matching
and the ID code is always considered to be non-matching, and connection of the on-chip debugger is prohibited.
Furthermore, if all bytes of the control code and ID code have the value FFh, there is no determination of matching, the
ID code is always considered to match, and connection of the on-chip debugger is allowed. See
Figure 39.23 for the
configuration of ID codes in flash memory.
39.12 ROM Code Protection
ROM code protection is a facility for prohibiting a PROM programmer from reading from or programming flash
memory. The ROM code in flash memory is a 32-bit code.
Figure 39.31 shows the configuration of the ROM code. Set
the ROM code in 32-bit units.
For release from ROM code protection, erase the EB00 block of the user mat that contains the ROM code in boot mode
or by user programming.
Figure 39.31
Configuration of ROM Code
Table 39.18
Specifications for ID Code Protection on Connection of the On-Chip Debugger
Control
Code
ID Code
State of
Protection
Operations at On-Chip Debugger Connection
FFh
FFh, …, FFh
(all bytes FFh)
Protection disabled The control code and ID code are not judged, the ID code always
matches, and connection to the on-chip debugger is permitted.
52h
50h, 72h, 6Fh, 74h, 65h,
63h, 74h, FFh, ..., FFh
Protection enabled
The control code and ID code are not judged, the ID code is always
non-matching, and connection to the on-chip debugger is prohibited.
Other than
above
Other than above
Protection enabled
Matching ID code: Authentication of the on-chip debugger is ended
and connection with the on-chip debugger is permitted.
Non-matching ID code: The ID code protection waiting state is
entered again.
Table 39.19
Specifications for ROM Code Protection
ROM Code
State of Protection
Operations at the Time of Connection with the PROM Programmer
0000 0000h
Protection enabled
(ROM code protection 1)
Access (both reading and writing) to the user mat and the user boot mat are prohibited.
0000 0001h
Protection enabled
(ROM code protection 2)
Reading from the user mat and the user boot mat are prohibited.
Other than above
Protection disabled
Access (both reading and writing) to the user mat and the user boot mat are permitted.
FFFF FF9Ch
31
0
ROM code