Programming Flash Eeprom, #$7FE | Motorola CMD912x, DG128, 68HC912

Programming Flash EEPROM

After debugging, you can program your application into Flash Memory so it executes automatically when you apply power to the board as follows:

1.Make a backup copy of HELLO.ASM then use a text editor to modify it.

2.Change the ORG location for the program start to the internal flash if needed.

3.Remove the comment ; character before one of the following lines to initialize the stack pointer which is necessary when running outside of a debugger:

LDS	#$3FFE	;	DG/DP128 or DP256 – initialize…
LDS	#$7FE	;	D60 - initialize the stack pointer

4.Remove the comment ; character from before the following 2 lines at the end, to set the reset vector to go to the beginning of the program (the label START) when powered on:

org	$fffe	reset vector
	fdb	START

5.Re-Assemble HELLO.ASM as described in the "Assembling Source Code" section.

6.Select Program from the AxIDE menu and follow the message prompts. When prompted for a file name, enter the new HELLO.S19 file.

7.Press the RESET button on the board before clicking OK. When prompted to Erase, choose Yes.

8.When finished programming, REMOVE POWER then set the MODE SWITCH positions 1 and 2 OFF. Note: turn position 3 off also for DP256 version.

9.Re-Apply Power to the board. Your new program should start automatically and the “Hello World” prompt should be displayed in the terminal window.

To return to the Mon12 monitor program, set the MODE SWITCH positions 1 and 2 back ON then press RESET. Note: MODE switch 3 also must be ON for DP256 1K79 and earlier mask sets.