MC68HC705P9 Datasheet, PDF (26/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Memory _EPROM/OTPROM
EPROM/
OTPROM
Programming
EPROM
Programming
Register
The two ways to program the EPROM/OTPROM are:
• Manipulating the control bits in the EPROM programming register
to program the EPROM/OTPROM on a byte-by-byte basis
• Activating the bootloader ROM to download the contents of an
external memory device to the on-chip EPROM/OTPROM
The EPROM programming register contains the control bits for
programming the EPROM/OTPROM.
$001C Bit 7
6
5
4
3
2
1
Read: 0
0
0
0
0
0
LATCH
Write: R
R
R
R
R
R
Reset: 0
0
0
0
0
0
0
R = Reserved
Figure 3. EPROM Programming Register (EPROG)
Bit 0
EPGM
0
LATCH — EPROM Bus Latch
This read/write bit latches the address and data buses for
EPROM/OTPROM programming. Clearing the LATCH bit
automatically clears the EPGM bit. EPROM/OTPROM data cannot be
read while the LATCH bit is set. Resets clear the LATCH bit.
1 = Address and data buses configured for EPROM/OTPROM
programming
0 = Address and data buses configured for normal operation
EPGM bit— EPROM Programming
This read/write bit applies the voltage from the IRQ/V_PP pin to the
EPROM/OTPROM. To write the EPGM bit, the LATCH bit must
already be set. Clearing the LATCH bit also clears the EPGM bit.
Resets clear the EPGM bit.
1 = EPROM/OTPROM programming power switched on
0 = EPROM/OTPROM programming power switched off
8-mc68hc705p9
26
Memory
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