GENERAL RELEASE SPECIFICATION
August 27, 1998
NOTE
While the PEPGM bit is set and the V voltage level is applied to the IRQ/V
PP
PP
pin, do not access bits that are to be left unprogrammed (erased).
To program the PEPROM, V must be greater than 4.5 Vdc.
DD
16.3 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.
Reading the PEPROM is easiest when each PEPROM column contains one byte.
Selecting a row 0 bit selects the first bit, and incrementing the PEPROM bit select
register (PEBSR) selects the next bit in row 1 from the same column. Increment-
ing PEBSR seven more times selects the remaining bits of the column and ends
up selecting the bit in row 0 of the next column, thereby setting the row 0 flag,
PEPRZF.
NOTE
A PEPROM byte that has been read can be transferred to the personality EPROM
bit select register (PEBSR) so that subsequent reads of the PEBSR quickly yield
that PEPROM byte.
16.4 PEPROM ERASING
MCUs with windowed packages permit PEPROM erasure with ultraviolet light.
2
Erase the PEPROM by exposing it to 15 Ws/cm of ultraviolet light with a wave-
length of 2537 angstroms. Position the ultraviolet light source 1 inch from the win-
dow. Do not use a shortwave filter. The erased state of a PEPROM bit is a logic
zero.
MOTOROLA
16-4
PERSONALITY EPROM
MC68HC05SB7
REV 2.1
FREESCALE [ Freescale ]
