MC68HC908JB8 Datasheet, PDF (62/286 Pages) Motorola, Inc – MICROCONTROLLERS

FLASH Memory
4.9.1 Variables
The ROM-resident routines use three variables: CTRLBYT, CPUSPD
and LADDR; and one data buffer. The minimum size of the data buffer
is one byte and the maximum size is 64 bytes.
CPUSPD must be set before calling the ERASE or PROGRAM routine,
and should be set to four times the value of the CPU internal bus speed
in MHz. For example: for CPU speed of 3MHz, CPUSPD should be set
to 12.
Table 4-2. ROM-Resident Routine Variables
Variable
CTRLBYT
CPUSPD
LADDR
DATABUF
Address
$0048
$0049
$004A–$004B
$004C–$008B
Description
Control byte for setting mass erase.
Timing adjustment for different CPU
speeds.
Last FLASH address to be programmed.
Data buffer for programming and verifying.
4.9.2 ERASE Routine
The ERASE routine erases the entire FLASH memory. The routine does
not check for a blank range before or after erase.
Table 4-3. ERASE Routine
Routine
ERASE
Calling Address $FC06
Stack Use
5 Bytes
Input
CPUSPD — CPU speed
HX —
Contains any address in the range to be
erased
CTRLBYT — Mass erase
Mass erase if bit 6 = 1
Technical Data
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MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
FLASH Memory
Freescale Semiconductor