The Microcontroller Idea Book - Jan Axelson's Lakeview Research

memory on bootup. This is what allows you to disconnect the system from its host and run
it as a stand-alone system.
You can also permanently store a value for MTOP in U8. If you have a 32K RAM at U7,
storing MTOP will ensure that you can use FPROG, and that your stored programs will be
preserved when you reboot or power down.
If U7 is 32K, type
MTOP=7FFFH
FPROG3
Now, when your system boots up, MTOP will automatically be set to 7FFFh. FPROG3 also
saves the baud rate and boots to the READY prompt without requiring you to press the space
bar.
If you want to save MTOP and also run a program on bootup, use FPROG4, which combines
the features of FPROG2 and FPROG3. FPROG5 is another useful command. It prevents
BASIC-52 from clearing external data memory on bootup. FPROG6 enables you to add
your own assembly-language reset routine.
If you use FPROG2-FPROG6, BASIC-52 will no longer auto-detect your host’s baud rate.
You must use the baud rate and crystal value that were in use when you executed the FPROG
command.
Erasing NV Memory
Saving Programs
Eventually, your NVRAM or EEPROM will fill with programs, or you may just want to
erase what you’ve stored and start fresh. Listing 4-1 is a program that erases U8 by writing
0FFh to all locations.
To use the program, enter the listing and type RUN. The READY prompt will return when
erasing is complete. Line 30 verifies each erasure, and is required only for EEPROM,
Listing 4-1. Erases NVRAM or EEPROM.
10 FOR I=8000H TO 9FFFH
20 XBY(I)=0FFH
30 IF XBY(I)0FFH THEN GOTO 30
40 NEXT I
50 END
The Microcontroller Idea Book 55