7
Programming External EEPROM
When finished with program development you can program your application into EEPROM so it
executes automatically when you apply power to the board. The following procedure does this:
1. Make a backup copy of the HELLO.ASM source code.
2. Use a text editor to modify HELLO.ASM. Change the start of the program to
$E000
which is
the beginning of the EEPROM in U7. Do this by changing the
”ORG $2400” to ”ORG
$E000”
.
3. Remove the comment
*
character from before the following lines also:
*
LDS
#$23FF
set the stack pointer
*eloop
nop
endless loop
*
bra
eloop
*
org
$FFFE
set the reset vector
*
fdb
START
4. This will initialize the stack pointer which is necessary when running outside of buffalo but
should not be done while running under buffalo since it must handle the stack; cause the
program to NOT try to "return" at the end and lastly, program the HC11 reset vector to go to
the beginning of the program (the label START) when powered on.
5. Re-Assemble HELLO.ASM as described in the "Assembling Source Code" section.
6. Select "Program” and enter your newly assembled HELLO.S19 file if not already there.
7. Make sure External EEPROM is selected in this dialog box then click OK and follow the
onscreen instructions (installing the programming jumpers then power off then on or press
the RESET switch).
8. When finished programming, remove the jumpers as instructed by the program.
9. Cycle power or press RESET on the board. Your new program should start automatically
and the “Hello World” prompt should be displayed in the terminal window.
To return to the buffalo monitor program, repeat the above steps starting with number 6,
substituting
BUF34X.S19
(in the AxIDE program directory) instead of HELLO.S19. The buffalo
monitor should execute again the next time the board is powered on.
