HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 597

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

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.
Note:
1
2
3
4
5
To prevent microcontroller errors caused by accidental programming or erasing, apply 12 V to V PP
only when the flash memory is programmed or erased, or when flash memory is emulated by RAM;
do not apply 12 V to the V PP 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 V PP on and
off, see section 18-10, Flash Memory Programming and Erasing Precautions.
Set MD
Execute user application program
Store user application programs
Transfer on-board update
Execute on-board update
Figure 18-13 User Program Mode Operation (Example)
Update flash memory
Apply 0 to 5 V to MD
2
(user program mode)
program into RAM
to MD
program in RAM
Wait 5 to 10 s
Set V
V
PP
0
= 12 V
to 101, 110, or 111
PP
E bit
2
588
Procedure
1. The user stores application programs in
2. Pin inputs are set up for user program
3. A reset starts the CPU, which transfers
4. Following a branch to the program in
5. After the on-board update ends, clear
flash memory. One of these is an on-
board update program that will execute
steps 3 to 5 below.
mode.
the on-board update program into RAM.
RAM, the on-board update program is
executed.
V
flash memory.
Wait 5 to 10µs to stabilize internal
power supply.
Update program is executed.
the V
the updated user application program
and this program is executed.
After clearing the V
flash memory program executes, flash
memory read setup time (t
needed.
PP
E bit in FLMCR is set to update
PP
E bit then a branch is made to
PP
E bit, before the
PRS
) is