MC68HC705J MOTOROLA [Motorola, Inc], MC68HC705J Datasheet - Page 40

• Manufacturer Part Number: MC68HC705J
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Memory
2.6.3 EPROM Erasing
2.7 Mask Option Register
Technical Data
40
NOTE:
Writing logic 1s to both the ELAT and EPGM bits with a single instruction
sets ELAT and clears EPGM. ELAT must be set first by a separate
instruction.
Bits [7:3] — Reserved
Take these steps to program a byte of EPROM/OTPROM:
The erased state of an EPROM bit is logic 0. Erase the EPROM by
exposing it to 15 Ws/cm
2537 angstroms. Position the ultraviolet light source one inch from the
EPROM. Do not use a shortwave filter.
The mask option register (MOR) is an EPROM/OTPROM byte that
controls these options:
1. Apply the programming voltage, V
2. Set the ELAT bit.
3. Write to any EPROM/OTPROM address.
4. Set the EPGM bit and wait for a time, t
5. Clear the ELAT bit.
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COP watchdog (enable or disable)
External interrupt pin triggering (edge-sensitive only or edge- and
level-sensitive)
Port A external interrupts (enable or disable)
Port pulldown resistors (enable or disable)
STOP instruction (stop mode or halt mode)
Crystal oscillator internal resistor (enable or disable)
EPROM security (enable or disable)
Short oscillator delay (enable or disable)
Memory
2
of ultraviolet light with a wave length of
PP
, to the IRQ/V
EPGM
MC68HC705J1A — Rev. 4.0
.
PP
pin.
MOTOROLA