tmp88cs38ng TOSHIBA Semiconductor CORPORATION, tmp88cs38ng Datasheet - Page 40

• Manufacturer Part Number: tmp88cs38ng
• Description: Cmos 8-bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

(2) Data replacement mode
area with the new instead of correcting the data reference instruction when that
reference data is changed.
However, when this mode is used, if there is a need to replace only the fixed data in
ROM, the instruction to reference this ROM data should be corrected. Thus, a large
amount of ROM is required for the patch program. To avoid this, the system has the
data replacement mode. With this mode, three consecutive bytes of data can be
replaced for each bank. (For an instruction which accesses only one byte, only the first
byte can be replaced. For an instruction which accesses only two bytes, the two
consecutive bytes can be replaced.) Setting ROMCCR CMx (x: 0 to 3) to “1” puts the
system in the data replacement mode. Specify the start address of ROM data to be
replaced as the corrective ROM address. Then, specify the new three-byte data as the
patch data.
Note: Corrective address must be assigned to 1st byte of instruction codes on the
Note: For data replacement mode, the corrective address should be the address of fixed
1.
2.
3.
4.
5.
6.
In the data replacement mode, the system replaces reference data stored in the ROM
The program jump mode reduces the complexity of correcting the processing routine.
Example 1: Setting the program correction circuit with the initial routine
0C020H
0C086H
program correction circuit's register as follows.
Read the flag, which indicates whether to use the program correction circuit, from
the external memory.
If that circuit is not used, perform normal initial processing.
If it is used, set CMx to “1” to establish the data replacement mode.
Read the address of the data to be replaced and the patch data from the external
memory.
Set the address and patch data, which were read in step “4.”, in ROMCDR.
Repeat steps “4.” and “5.” as many times as there are required banks.
00FFFH
0C085H
FFFFFH
00000H
0003FH
00040H
0083FH
00F80H
04000H
Using the initial routine program, which is executed right after reset, set the
program jump mode.
data (including a vector). (The operation code and operand cannot be changed.)
Bug area
ROM
RAM
DBR
SFR
88CS38-40
JP 0C086H
program
Return
Patch
006EFH
006F0H
00600H
TMP88CS38/CM38A/CP38A
2007-09-12