Datasheet

EEPROM 4K
MC9S12DP256 — Revision 1.1
EEPROM 4K
EPROT Ñ EEPROM
Protection
Register
Read: Anytime
Write: Only in special modes
This register is banked.
The EEPROM protection registers are loaded during the reset sequence
from address $_FFD as indicated by the “F” in the reset row of the
register diagram. This register determines whether the whole block or a
subsection of the block is protected against accidental program or erase.
The protected area grows downwards from $xFFF. This area may be
used to keep critical parameters. Trying to alter the protected area will
result in a protect violation error and bit PVIOL will be set in the
EEPROM Status Register ESTAT. A mass erase of the full 4k byte block
is only possible when EPDIS is set.
In order to change the EEPROM protection in special modes, the
protection register can be written directly.
In order to change the protection in user mode the EEPROM location
$_FFD has to be re-programmed and the MCU reset to reload the
EPROT register from that EEPROM location.
The size of the protected range is determined by EP[2:0]. The protection
is disabled by the bit EPDIS.
EPOPEN — Opens the EEPROM block or a subsection of it for program
or erase.
1 = The EEPROM block or subsections are enabled to program or
erase.
0 = The whole EEPROM block is protected. In this case the other
bits within the protect register are don’t care.
Address Offset: $0004
Bit 7 654321Bit 0
Read: EPOPEN F F F EPDIS EP2 EP1 EP0
Write:
Reset: FFFFFFFF
= Reserved or unimplemented
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
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