AN1836 Motorola / Freescale Semiconductor, AN1836 Datasheet - Page 7

• Manufacturer Part Number: AN1836
• Description: FLASH Programming for Motorola MC68HC912 Microcontrollers
• Manufacturer: Motorola / Freescale Semiconductor

General Notes
on Coding FLASH
Programming
and Erasing
AN1836
MOTOROLA
NOTE:
The routines that follow were tested with version 2.15 of SDBUG12
running on a Windows NT workstation in a DOS window. The problem
described in the preceding paragraph did not appear when executing
these routines. SDBUG12 displayed the proper values for the FLASH
array when the routines were allowed to run to completion. Both of the
code segments included here can be loaded into the RAM of the part at
the same time since they do not overlap. Use the LOAD command in
SDBUG12 to load each segment into RAM. Notice that the entry point of
the program routine is $80A and the entry point of the erase routine is
$90A. Once loaded into RAM, the command G 80A will begin the
programming process or G 90A will begin the erase process.
For a detailed description of the software commands for SDBUG12,
refer to documentation from P&E Microcomputer Systems, Inc.
Once the FLASH array has been erased or programmed, reloading the
DBUG12 monitor code into the FLASH array is necessary if that monitor
is to be used, as manipulation of the array will have destroyed this code.
This can be accomplished with the bootloader in the boot block of the
part or by using a software programming tool, such as Prog12s, which is
a product of P&E Microcomputer Systems, Inc.
If using the M68EVB912B32 evaluation board, refer to the Evaluation
Board User’s Manual, which comes with the evaluation board, for further
information on how to reload the monitor program into the device using
the on-board bootloader.
The routines used in this application note are designed for reference
purposes. Programming and erase routines always should be
downloaded to the device at the time of programming through the BDM
or through a CAN, J1850, or other communication link. The code for
these algorithms should not be resident on the device during normal
operations.
One reason for not including these routines in FLASH or EEPROM is to
prevent possible activation in a code runaway situation. If the code gets
Windows NT is a registered trademark of Microsoft in the U.S. and other countries.
Software Considerations
Application Note
7