MC68HC705JJ7 Datasheet, PDF (119/164 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 13
EPROM/OTPROM
13.1 Introduction
This section describes how to program the 6160-byte erasable programmable read-only
memory/one-time programmable read-only memory (EPROM/OTPROM), the mask option register
(MOR), and the EPROM security bit (EPMSEC).
NOTE
In packages with no quartz window, the EPROM functions as one-time
programmable ROM (OTPROM).
13.2 EPROM Registers
The EPROM programming register (EPROG) controls the actual programming of the EPROM bytes and
the mask option register (MOR). The MOR controls eight mask options found on the read-only memory
(ROM) version of this microcontroller unit (MCU). There is an additional EPROM bit (EPMSEC) located
at the computer operating properly (COP) address to provide EPROM array security.
13.2.1 EPROM Programming Register
The EPROM programming register (EPROG) shown in Figure 13-1 contains the control bits for
programming the EPROM. In normal operation, the EPROM programming register contains all logic 0s.
Address:
Read:
Write:
Reset:
$001C
Bit 7
6
5
4
3
2
1
0
0
0
0
0
ELAT MPGM
R
R
R
R
0
0
0
0
0
0
0
= Unimplemented
R
= Reserved for test
Figure 13-1. EPROM Programming Register (EPROG)
Bit 0
EPGM
0
EPGM — EPROM Programming Bit
This read/write bit applies the voltage from the IRQ/V_PP pin to the EPROM. To write the EPGM bit, the
ELAT bit must already be set. Clearing the ELAT bit also clears the EPGM bit. Reset clears EPGM.
1 = EPROM programming power switched on
0 = EPROM programming power switched off
MPGM — Mask Option Register (MOR) Programming Bit
This read/write bit applies programming power from the IRQ/V_PP pin to the MOR. Reset clears MPGM.
1 = MOR programming power switched on
0 = MOR programming power switched off
MC68HC705JJ7 • MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
Freescale Semiconductor
119