HD6433044 Datasheet, PDF(584/867 Page) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

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HD6433044 Datasheet, PDF (584/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

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Bit 7âProgramming Power (VPP): Programming power bit (VPP) detects VPP, and level is

displayed as â1â or â0.â The permissible output currents for impressed high voltage VH are given

in 21.3.1, âDC Characteristics.â The value of VH ranges from VCC + 2 V to 11.4 V. If a voltage in

excess of VH is applied, â1â is displayed; otherwise â0â is displayed.

This bit restricts the hardware protect functions during write and erase operations for the flash

memory. For details on hardware protect, see 18.7.8, âProtect Modes.â For notes on VPP usage,

see 10.10, âFlash Memory Programming and Erasing Precautions.â

Bit 7

VPP

Description

0

[Clear conditions]

(Initial value)

This is the regular operational mode when a voltage exceeding

VH is not applied to the VPP pin. The flash memory cannot be

written or erased. âHardware Protectâ is displayed.

1

[Set conditions]

This is the operational mode when a voltage exceeding VH is

applied to the VPP pin. The flash memory can be written and

erased. âHardware Protect Disabledâ is displayed*.

Note: For correct write and erase functions, the setting should be VPP = 12.0 V to 0.6 V (11.4 V to

12.6 V).

Bit 6âVPP Enable (VPPE): Disables or enables 12-V application to the VPP pin. After this bit is

set, it is necessary to wait for at least 5 Âµs for the internal power supply to stabilize; programming

and erasing cannot be performed until stabilization is complete. After this bit is cleared, it is

necessary to wait for the flash memory read setup time (tFRS) in order to read flash memory.

Bit 6

VPPE

0

1

Description

VPP pin 12-V power supply is disabled

VPP pin 12-V supply is enabled

(Initial value)

Note: The power supply system used for the flash memory is switched by means of the VppE bit.

After switching, operation is not guaranteed during the period before the power supply

system stabilizes. It is therefore prohibited to fetch from flash memory and execute an

instruction that sets or resets the VppE bit.

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