MC68HC705JJ7 Datasheet, PDF (122/164 Pages) Freescale Semiconductor, Inc – Microcontrollers

EPROM/OTPROM
13.2.3 EPROM Security Bit
An EPROM programmable bit is provided at the location of the COP watchdog register at $1FF0 as shown
in Figure 13-3. This bit allows control of access to the EPROM array. Any accesses of the EPROM
locations will return undefined results when the EPMSEC bit is set. Refer to 13.3.2 EPMSEC
Programming for programming instructions.
Address: $1FF0
Bit 7
6
5
4
3
2
1
Bit 0
Read:
OPT
Write: EPMSEC
COPC
Reset:
Unaffected by reset
Erased:
0
—
—
—
—
—
—
—
= Unimplemented
Figure 13-3. EPROM Security in COP and Security Register (COPR)
EPMSEC — EPROM Security⁽¹⁾
This EPROM write-only bit enables the access to the EPROM array.
1 = Access to the EPROM array in non-user modes is denied.
0 = Access to the EPROM array in non-user modes is enabled.
13.3 EPROM Programming
A programming board is available from Freescale to download to the on-chip EPROM/OTPROM using
the factory-provided programming software. Factory-provided software for programming the PEPROM is
available on the World Wide Web at:
http://www.freescale.com
The programming software copies to the 6144-byte space located at EPROM addresses $0700–$1EFF
and to the 16-byte space at addresses $1FF0–$1FFF which includes the mask option register at address
$1FF1, and the security bit at address $1FF0.
NOTE
To program the EPROM/OTPROM, MOR, or EPMSEC bits properly, the
V_DD voltage must be greater than 4.5 volts.
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or copying the EPROM/OTPROM
difficult for unauthorized users.
MC68HC705JJ7 • MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
122
Freescale Semiconductor