68HC705SP7 datasheet(176/230 Pages) FREESCALE

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Personality EPROM

General Release Specification

MC68HC705JJ7/MC68HC705JP7 — Rev. 3.0

Personality EPROM

12.4 PEPROM Programming

Factory-provided software for programming the PEPROM is available

through the Motorola Freeware Bulletin Board Service (BBS). The

number is (512) 891-FREE. After making the connection, type bbs in

lowercase letters. Then press the return key to start the BBS software.

NOTE:

While the PEPGM bit is set and the VPP voltage level is applied to the

IRQ/VPP pin, do not access bits that are to be left unprogrammed

(erased).

To program the PEPROM bits properly, the VDD voltage must be greater

than 4.5 Vdc.

The PEPROM can also be programmed by user software with the VPP

voltage level applied to the IRQ/VPP pin. The following sequence shows

how to program each PEPROM bit:

1. Select a PEPROM bit by writing to the PEBSR.

2. Set the PEPGM bit in the PESCR.

3. Wait for the programming time, tEPGM.

4. Clear the PEPGM bit.

5. Move to next PEPROM bit to be programmed in step 1.

12.5 PEPROM Reading

The following sequence shows how to read the PEPROM:

1. Select a bit by writing to the PEBSR.

2. Read the PEDATA bit in the PESCR.

3. Store the PEDATA bit in RAM or in a register.

4. Select another bit by changing the PEBSR.

5. Continue reading and storing the PEDATA bits until the required

personality EPROM data is retrieved and stored.

Freescale Semiconductor, Inc.

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