HD6433640 HITACHI [Hitachi Semiconductor], HD6433640 Datasheet - Page 159

• Manufacturer Part Number: HD6433640
• Description: H8/3644 Series Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

Hardware Protection: Hardware protection refers to a state in which programming/erasing of
flash memory is forcibly suspended or disabled. At this time, the flash memory control register
(FLMCR) and erase block register (EBR1 and EBR2) settings are cleared.
Details of the hardware protection states are given below.
Item
Programming
voltage (FV
protect
Reset/standby
protect
Notes: 1. Three modes: program-verify, erase-verify, and prewrite-verify.
If an interrupt is generated while the flash memory is being programmed or erased (while the P or
E bit is set in FLMCR), an operating state may be entered in which the vector will not be read
correctly in the exception handling sequence, resulting in program runaway. All interrupt sources
should therefore be masked to prevent interrupt generation while programming or erasing the flash
memory.
150
6.7.9
2. All blocks are erase-disabled, and individual block specification is not possible.
3. For details, see section 6.9, Flash Memory Programming and Erasing Precautions.
4. For details, see AC Characteristics in section 13, Electrical Characteristics.
Interrupt Handling during Flash Memory Programming/Erasing
PP
)
Description
When 12 V is not being applied to the
FV
are initialized, and the program/erase-
protected state is entered. To obtain
this protection, the V
not exceed the V
voltage.*
In a reset, (including a watchdog timer
reset), and in sleep, subsleep, watch,
and standby mode, FLMCR, EBR1,
and EBR2 are initialized, and the
program/erase-protected state is
entered. In a reset via the RES pin, the
reset state is not reliably entered
unless the RES pin is held low for at
least 20 ms (oscillation settling time)*
after powering on. In the case of a
reset during operation, the RES pin
must be held low for a minimum of 10
system clock cycles (10ø).
PP
pin, FLMCR, EBR1, and EBR2
3
CC
power supply
PP
voltage should
4
Program
Disabled
Disabled
Erase
Disabled*
Disabled*
Functions
2
2
Verify*
Disabled
Disabled
1