MC68HC11F1 Datasheet, PDF (29/68 Pages) Motorola, Inc – Technical Summary 8-Bit Microcontroller

6 Electrically Erasable Programmable ROM
The MC68HC11F1 has 512 bytes of electrically erasable programmable ROM (EEPROM). A nonvola-
tile, EEPROM-based configuration register (CONFIG) controls whether the EEPROM is present or ab-
sent and determines its position in the memory map. In single-chip and bootstrap modes the EEPROM
is positioned at $FE00–$FFFF. In expanded and special test modes, the EEPROM can be repositioned
to any 4-Kbyte boundary ($xE00–$xFFF).
NOTE
EEPROM is available on the MC68HC11F1 only.
6.1 EEPROM Operation
The EEON bit in CONFIG controls whether the EEPROM is present in the memory map. When
EEON = 1, the EEPROM is enabled. When EEON = 0, the EEPROM is disabled and removed from the
memory map. EEON is forced to one out of reset in single-chip and special bootstrap modes to enable
EEPROM. EEON is forced to zero out of reset in special test mode to remove EEPROM from the mem-
ory map, although test software can turn it back on. In normal expanded mode, EEON is reset to the
value last programmed into CONFIG.
An on-chip charge pump develops the high voltage required for programming and erasing. When the
E-clock frequency is 1 MHz or above, the charge pump is driven by the E-clock. When the E-clock fre-
quency is less than 1 MHz, select the internal RC oscillator to drive the EEPROM charge pump by writ-
ing one to the CSEL bit in the OPTION register. Refer to the discussion of the OPTION register in 4.3
System Initialization Registers, page 23.
6.2 EEPROM Registers
BPROT — Block Protect
Bit 7
6
0
0
RESET
0
0
5
4
3
2
1
Bit 0
0
PTCON BPRT3 BPRT2 BPRT1 BPRT0
0
1
1
1
1
1
Bits [7:5] — Not implemented. Reads always return zero and writes have no effect.
PTCON — Protect for CONFIG
0 = CONFIG register can be programmed or erased normally
1 = CONFIG register cannot be programmed or erased
BPRT[3:0] — Block Protect Bits for EEPROM
0 = Protection disabled
1 = Protection enabled
Table 14 Block Protect Bits for EEPROM
Bit Name
BPRT3
BPRT2
PBRT1
BPRT0
Block Protected
$xEE0–xFFF
$xE60–xEDF
$xE20–xE5F
$xE00–xE1F
Block Size
288 Bytes
128 Bytes
64 Bytes
32 Bytes
$x035
NOTE
Block protect register bits can be written to zero (protection disabled) only once
within 64 cycles of a reset in normal modes, or at any time in special modes. Block
protect register bits can be written to one (protection enabled) at any time.
MC68HC11F1/FC0
MC68HC11FTS/D
MOTOROLA
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