H8SLASH3021 datasheet(495/712 Pages) RENESAS

495 / 712 page

15. ROM

Rev.2.00 Mar. 22, 2007 Page 471 of 684

REJ09B0352-0200

FWE=high

(user program mode)

Branch to program in RAM.

Transfer on-board programming

program to RAM.

Reset start

MD2 to MD0 = 101, 110, 111

Execute on-board programming

program in RAM

(flash memory reprogramming).

Input low level to FWE after SWE

bit clear (user program mode exit)

Execute user application

program in flash memory.

The user writes a program that executes steps 3 to 8 in advance

as shown below .

Sets the mode pin to an on-chip ROM enable mode

(mode 5, 6, or 7).

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.*1)

Transfers the on-board programming program to RAM.

Branches to the program in RAM.

Sets the FWE pin to a high level. *2

(Switches to user program mode.)

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.

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. *3

Branches to, and executes, the user application program

reprogrammed in flash memory.

Notes: 1. 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.

Also, while a high level is applied to the FWE pin, the

watchdog timer should be activated to prevent

overprogramming or overerasing due to program

runaway, etc.

2. For notes on FWE pin High/Low, see section 15.11,

Notes on Flash Memory Programming/Erasing.

3. In order to execute a normal read of flash memory in

user program mode, the program/erase program must

not be executing. It is thus necessary to ensure that

bits 6 to 0 in FLMCR1 are cleared to 0.

Figure 15.9 User Program Mode Execution Procedure (Example)

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