User`s manual

Engineering Bulletin
EB183 — Rev. 1.0
6 MOTOROLA
Software Considerations
Using SDBUG12 to manipulate the FLASH EEPROM requires some
special considerations. First, a few bugs in some versions of the
software can cause some confusion when manipulating the FLASH
memory array. The memory display windows sometimes do not refresh
properly, especially when manually erasing the array by manipulating
the control registers using the mm command. Once the erase voltage
has been applied by modifying the FEECTL register, the display often
shows all of the odd addresses as one value and all the even addresses
as another value. To fix this problem, issue a reset command from the
SDBUG12 command prompt to force SDBUG12 to refresh all of its
display windows from the microcontroller once the part comes out of
reset.
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. The code
segments included here can both be loaded into the RAM of the part,
using the load command in SDBUG12. 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, g 80A will begin the programming process or
g 90A will begin the erase process.
NOTE: Once the FLASH array has been erased or programmed, reloading the
DBUG12 monitor into the FLASH array is necessary if you wish to use
it, as manipulation of the array will destroy the monitor program code.
This can be accomplished with the bootloader in the boot block of the
part or by using Prog12s.
If using the M68EVB912B32 evaluation board, refer to Appendix E of the
Evaluation Board User’s Manual (Motorola order number
68EVB912B32UM/D), for further information on how to reload the
monitor program into the device using the on-board bootloader.