HD6433044 Datasheet, PDF(597/867 Page) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

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HD6433044 Datasheet, PDF (597/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

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The flash memory cannot be read while being programmed or erased, so the update program must

either be stored in external memory, or transferred temporarily to the RAM area and executed in

RAM.

User Program Mode Execution Procedure: Figure 18-13 shows the procedure for user program

mode execution in RAM.

1

Store user application programs

Set MD2 to MD0 to 101, 110, or 111

Apply 0 to 5 V to MD2

2

VPP = 12 V

(user program mode)

3

Transfer on-board update

program into RAM

Execute on-board update

program in RAM

Set VPPE bit

4

Wait 5 to 10 Âµs

Update flash memory

5

Execute user application program

Procedure

1. The user stores application programs in

flash memory. One of these is an on-

board update program that will execute

steps 3 to 5 below.

2. Pin inputs are set up for user program

mode.

3. A reset starts the CPU, which transfers

the on-board update program into RAM.

4. Following a branch to the program in

RAM, the on-board update program is

executed.

VPPE bit in FLMCR is set to update

flash memory.

Wait 5 to 10Âµs to stabilize internal

power supply.

Update program is executed.

5. After the on-board update ends, clear

the VPPE bit then a branch is made to

the updated user application program

and this program is executed.

After clearing the VPPE bit, before the

flash memory program executes, flash

memory read setup time (tPRS) is

needed.

Note:

To prevent microcontroller errors caused by accidental programming or erasing, apply 12 V to VPP

only when the flash memory is programmed or erased, or when flash memory is emulated by RAM;

do not apply 12 V to the VPP pin during normal operation. While 12 V is applied, the watchdog

timer should be running and enabled to halt runaway program execution, so that program runaway

will not lead to overprogramming or overerasing. For further information about turning VPP on and

off, see section 18-10, Flash Memory Programming and Erasing Precautions.

Figure 18-13 User Program Mode Operation (Example)

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