Renesas F-ZTAT H8 Series Hardware Manual page 609

MD – MD = 101, 110, 111
1
2 0
Reset start
2
Transfer on-board programming
3
program to RAM
4 Branch to program in RAM
FWE = high
5
(user program mode)
Execute on-board programming
6
program in RAM
(flash memory reprogramming)
Input low level to FWE after SWE1
7
and SWE2 bits clear
(user program mode exit)
Execute user application
8
program in flash memory
Figure 18.10 User Program Mode Execution Procedure (Example)
Note: Normally do not apply a high level to the FWE pin. To prevent erroneous programming or
erasing in the event of program runaway, etc., apply a high level to the FWE pin only
when programming/erasing flash memory (including flash memory emulation by RAM).
If program runaway, etc. causes overprogramming or overerasing of flash memory, the
memory cells will not operate normally.
Procedure
The user writes a program that executes steps
3 to 8 in advance as shown below.
1. Sets the mode pin to an on-chip ROM
enable mode (mode 5, 6, or 7).
2. Starts the CPU via reset.
(The CPU can also be started from the user
program mode by setting the FWE pin to
high level during reset; that is, during the
period the RES pin is a low level.) *
3. Transfers the on-board programming
program to RAM.
4. Branches to the program in RAM.
5. Sets the FWE pin to a high level. *
(Switches to user program mode.)
6. After confirming that the FWE pin is a high
level, executes the on-board programming
program in RAM. This reprograms the user
application program in flash memory.
7. At the end of reprograming, clears the
SWE1 and SWE2 bit, and exits the user
program mode by switching the FWE pin
from a high level to a low level. *
8. Branches to, and executes, the user
application program reprogrammed in flash
memory.
Note: * For notes on FWE pin High/Low, see
section 18.11, Notes on Flash Memory
Programming/Erasing.
Rev. 3.00 Mar 21, 2006 page 581 of 814
Section 18 ROM
REJ09B0302-0300