Flash EEPROM
Flash EEPROM Control Block
68HC(9)12DG128 Rev 1.0
MOTOROLA
Flash EEPROM
93
program/erase voltage is provided to the Flash EEPROM module via an
external V
FP
pin. To prevent damage to the flash array, V
FP
should
always be within the specification as defined in
Table 68
in
Electrical
Characteristics
. Programming is by byte or aligned word. The Flash
EEPROM module supports bulk erase only.
The Flash EEPROM module has hardware interlocks which protect
stored data from accidental corruption. An erase- and
program-protected 8-Kbyte block for boot routines is located at the top
of each 32-Kbyte array. Since boot programs must be available at all
times, the only useful boot block is at $E000–$FFFF location. All paged
boot blocks can be used as protected program space if desired.
Flash EEPROM Control Block
A 4-byte register block for each module controls the Flash EEPROM
module operation. Configuration information is specified and
programmed independently from the contents of the Flash EEPROM
array. At reset, the 4-byte register section starts at address $00F4 and
points to the 00FEE32K register block.
Flash EEPROM Arrays
After reset, a fixed 32K Flash EEPROM array, 11FEE32K, is located
from addresses $4000 to $7FFF and from $C000 to $FFFF. The other
three 32K Flash EEPROM arrays 00FEE32K, 01FEE32K and
10FEE32K, are mapped through a 16K byte program page window
located from addresses $8000 to $BFFF. The page window has eight
16K byte pages. The last two pages also map the physical location of the
fixed 32K Flash EEPROM array 11FEE32K. In expanded modes, the
Flash EEPROM arrays are turned off. See
Operating Modes
.
3-flash