MC68HC705KJ1 Datasheet, PDF(26/108 Page) Motorola, Inc

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MC68HC705KJ1 Datasheet, PDF (26/108 Pages) Motorola, Inc – HCMOS Microcontroller Unit

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Memory

2.7.2 EPROM Programming Register

The EPROM programming register (EPROG) contains the control bits for programming the

EPROM/OTPROM.

Address:

Read:

Write:

Reset:

$0018

Bit 7

ELAT MPGM

= Unimplemented

= Reserved

Figure 2-3. EPROM Programming Register (EPROG)

Bit 0

EPGM

ELAT â EPROM Bus Latch Bit

This read/write bit latches the address and data buses for EPROM/OTPROM programming. Clearing

the ELAT bit automatically clears the EPGM bit. EPROM/OTPROM data cannot be read while the

ELAT bit is set. Reset clears the ELAT bit.

1 = Address and data buses configured for EPROM/OTPROM programming the EPROM

0 = Address and data buses configured for normal operation

MPGM â MOR Programming Bit

This read/write bit applies programming power from the IRQ/VPP pin to the mask option register. Reset

clears MPGM.

1 = Programming voltage applied to MOR

0 = Programming voltage not applied to MOR

EPGM â EPROM Programming Bit

This read/write bit applies the voltage from the IRQ/VPP pin to the EPROM. To write the EPGM bit, the

ELAT bit must be set already. Reset clears EPGM.

1 = Programming voltage (IRQ/VPP pin) applied to EPROM

0 = Programming voltage (IRQ/VPP pin) not applied to EPROM

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] â Reserved

Take the following steps to program a byte of EPROM/OTPROM:

1. Apply the programming voltage, VPP, to the IRQ/VPP pin.

2. Set the ELAT bit.

3. Write to any EPROM/OTPROM address.

4. Set the EPGM bit and wait for a time, tEPGM.

5. Clear the ELAT bit.

2.7.3 EPROM Erasing

The erased state of an EPROM bit is logic 0. Erase the EPROM by exposing it to 15 Ws/cm2 of ultraviolet

light with a wavelength of 2537 angstroms. Position the ultraviolet light source one inch from the EPROM.

Do not use a shortwave filter.

MC68HC705KJ1 â¢ MC68HRC705KJ1 â¢ MC68HLC705KJ1 Data Sheet, Rev. 4.1

Freescale Semiconductor

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