h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 653

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

21.6.2
When set to user program mode, the chip can program and erase its flash memory by executing a
user program/erase control program. Therefore, on-board reprogramming of the on-chip flash
memory can be carried out by providing on-board supply of programming data, and storing a
program/erase control program in part of the program area as necessary.
To select user program mode, select a mode that enables the on-chip flash memory (mode 2 or 3).
In this mode, on-chip supporting modules other than flash memory operate as they normally
would in mode 2 and 3.
The flash memory itself cannot be read while the SWE bit is set to 1 to perform programming or
erasing, so the control program that performs programming and erasing should be run in on-chip
RAM or external memory.
Figure 21.11 shows the procedure for executing the program/erase control program when
transferred to on-chip RAM.
Note: The watchdog timer should be activated to prevent overprogramming or overerasing
Section 21 ROM
User Program Mode
due to program runaway, etc.
Figure 21.11 User Program Mode Execution Procedure
(Mask ROM Version, H8S/2138 F-ZTAT, H8S/2134 F-ZTAT, and H8S/2132 F-ZTAT)
Write the transfer program (and the program/
erase control program if necessary) beforehand
Branch to flash memory application
program (flash memory rewriting)
Branch to program/erase control
Transfer program/erase control
Execute program/erase control
program in RAM area
MD1, MD0 = 10, 11
program to RAM
Reset-start
program
Rev. 4.00 Jun 06, 2006 page 599 of 1004
REJ09B0301-0400