Freescale Semiconductor, Inc.
Operating Modes and On-Chip Memory
3.6 EPROM, EEPROM and CONFIG register
3.6.1 EPROM
Using the on-chip EPROM programming feature requires an external
power supply (VPPE). Normal programming is accomplished using the
EPROG register. Program EPROM at room temperature only and place
an opaque label over the quartz window after programming.
The erased state of each EPROM byte is $FF.
3.6.1.1 EPROG — EPROM programming control register
State
on reset
Address bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
EXCO EXRO
EPROM programming (EPROG) $002B MBE
0
ELAT
0
0
EPGM 0000 0000
L
W
MBE — Multiple byte program enable
1 = Program four bytes with the same data.
0 = Normal programming.
When programming four bytes simultaneously, address bits 7 and 4
are ignored, hence a write to, for example, $99 will actually program
$09, $19, $89 and $99 (i.e. %x00x 1001). This bit may be read or
written only in special modes; it will always read zero in normal
modes.
Bits 6, 2, 1 — Not implemented; always read zero.
ELAT — EPROM latch control
1 = EPROM address and data buses configured for programming.
EPROM cannot be read.
0 = EPROM address and data buses configured for normal
operation.
When set, this bit causes the address and data for writes to the
EPROM to be latched. ELAT may be read and written at any time.
Technical Data
MC68HC11P2 — Rev 1.0
Operating Modes and On-Chip Memory
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