MC68HC705K1 Datasheet, PDF (96/140 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Personality EPROM (PEPROM)
10.4 PEPROM Programming
Factory-provided software for programming the PEPROM is available
through the Motorola web site at:
htt://mcu.motsps.com
The circuit shown in Figure 9-2. Programming Circuit can be used to
program the PEPROM with the factory-provided programming software.
NOTE:
To program the PEPROM, V_DD must be greater than 4.5 Vdc.
The PEPROM can also be programmed by user software with V_PP
applied to the IRQ/V_PP pin. This sequence shows how to program each
PEPROM bit:
1. Select a PEPROM bit by writing to PEBSR.
2. Set the PEPGM bit in PESCR.
3. Wait 3 ms.
4. Clear the PEPGM bit.
NOTE: While the PEPGM bit is set and V_PP is applied to the IRQ/V_PP pin, do not
access bits that are to be left unprogrammed (erased).
In 3-pin RC oscillator configurations, the PEPROM cannot be
programmed by user software. If the voltage on IRQ/V_PP is raised above
V_DD, the oscillator will revert to a 2-pin oscillator configuration and
device operation will be disrupted.
10.5 PEPROM Reading
This sequence shows how to read the PEPROM:
1. Select a bit by writing to PEBSR.
2. Read the PEDATA bit in PESCR.
3. Store the PEDATA bit in RAM or in a register.
4. Select another bit by changing PEBSR.
5. Continue reading and storing the PEDATA bits until the required
personality EPROM data is stored.
Technical Data
Personality EPROM (PEPROM)
For More Information On This Product,
Go to: www.freescale.com
MC68HC705K1 — Rev. 2.0