HD64F3048F16 Datasheet, PDF (627/903 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 18 ROM (H8/3048F-ONE: Single Power Supply, H8/3048B Mask ROM Version)
Since the flash memory cannot be read while it is being programmed/erased, place a programming
program on external memory, or transfer the programming program to RAM area, and execute it
in the RAM.
Figure 18.11 shows the procedure for executing when transferred to on-chip RAM. During reset
start, starting from the user program mode is possible.
1
MD₂–MD₀ = 101, 110, 111
2
Reset start
3
Transfer programming/erasing
program to RAM
4 ^{Branch to programming/erasing}
program in RAM area
5
FWE = high
(user program mode)
Execute programming/erasing
6
program in RAM
(flash memory reprogramming)
Input low level to FWE
7
after SWE bit clear
(user program mode exit)
8
Execute user application
program in flash memory
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 programming/erasing program
to RAM.
4. Branches to the program in RAM area.
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 programming/erasing
program in RAM. This reprograms the user
application program in flash memory.
7. At the end of reprograming, clears the SWE
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.
Figure 18.11 User Program Mode Execution Procedure (Example)
Rev. 3.00 Sep 27, 2006 page 599 of 872
REJ09B0325-0300