The Microcontroller Idea Book - Jan Axelson's Lakeview Research

Saving Programs
4
Saving Programs
In Chapter 3’s experiments, the BASIC-52 programs that you wrote were stored in RAM.
This is fine for temporary use, but every time you power down, your program disappears
and you have to start over.
This chapter shows you two ways to save BASIC-52 programs more permanently: by adding
nonvolatile memory to the BASIC-52 system, and by downloading your programs to your
host system’s disk. The nonvolatile memory may be battery-backed RAM, EEPROM, or
EPROM. You can also use this memory for storing assembly-language programs or data
that you want to save when you power down or reset. Disk storage is a convenient way to
save programs if you want to edit them off-line, upload them to a different BASIC-52 system,
or just save back-up copies.
Nonvolatile Memory Options
One of BASIC-52’s handiest features is its programming commands that store programs in
nonvolatile (NV) memory: EPROM, EEPROM, or battery-backed RAM. The commands
assume that the NV memory is addressed beginning at 8000h in external data memory.
With the addition of NV memory, you have two areas that may contain BASIC-52 programs:
the NV memory, addressed beginning at 8000h, and the RAM, addressed beginning at 0. To
distinguish between the two areas, you can call the memory beginning at 8000h the EPROM
The Microcontroller Idea Book 47