Freescale Semiconductor, Inc.
EPROM/ OTPROM
13.4.2 EPMSEC Prog ra m m ing
The state of the EPMSEC security bit should be programmed using the
programmer board. To program the EPMSEC bit, the desired state must
be written to the COP address and then the MPGM bit in the EPROG
register must be used. The following sequence will program the
EPMSEC bit:
1. Write the desired data to bit 7 of the COP location ($1FF0).
2. Apply the programming voltage to the IRQ/V pin.
PP
3. Set the MPGM bit in the EPROG.
4. Wait for the programming time, t
.
MPGM
5. Clear the MPGM bit in the EPROG.
6. Remove the programming voltage from the IRQ/V pin.
PP
Once the EPMSEC bit has been programmed to a logical one, access to
the contents of the EPROM and MOR in the expanded non-user modes
will be denied. It is therefore recommended that the user EPROM and
MOR in the part first be programmed and fully verified before setting the
EPMSEC bit.
13.5 EPROM Era sing
MCUs with windowed packages permit EPROM erasure with ultraviolet
2
light. Erase the EPROM by exposing it to 15 Ws/cm of ultraviolet light
with a wavelength of 2537 angstroms. Position the ultraviolet light
source 1 inch from the window. Do not use a shortwave filter. The erased
state of an EPROM bit is a logic zero.
NOTE: Unlike many commercial EPROMs, an erased EPROM byte will read as
$00. All unused locations should be programmed as zeros.
General Release Specification
MC68HC705JJ7/MC68HC705JP7 — Rev. 3.0
EPROM/OTPROM
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