The Microcontroller Idea Book - Jan Axelson's Lakeview Research

14-1 for longer delays between writes. To do so, between lines 30 and 40, add this or a
similar “do-nothing” loop: FOR J=1 to 10:NEXT J.
For EPROM storage, you can copy the ROM into RAM and then use Listing 13-8 to program
an EPROM. For this method, use a 32K RAM at U7 in Figure 3-1. You’ll also need an
unprogrammed 8K EPROM accessed as data or code/data memory. Set MTOP to 5FFFh or
lower to ensure that BASIC-52 won’t overwrite the area from 6000h to 7FFFh. In Listing
14-1, lines 10, 30, and 80, change 8000h to 6000h. Run the revised program to copy the
8052-BASIC’s ROM into RAM at 6000h-7FFFh. You then can upload or enter Listing 13-8
to copy BASIC-52 into your EPROM, at the starting address you specify.
Another option is to use an EPROM programmer to copy BASIC-52. If your programmer
has an adapter for 8051s, you can copy the 8052-BASIC’s ROM directly into the programmer’s
buffer and then program an EPROM, EEPROM, or NV RAM with the buffer’s
contents. If you don’t have an adapter, you can use the technique described above to copy
BASIC-52 into NV RAM or EEPROM, and then read the device into your programmer.
To read a DS1225 into an EPROM programmer’s buffer, configure the programmer for a
DS1225 or 2764 EPROM, since the pinouts for reading these devices are the same. Place
the DS1225 in the programming socket and read the contents into the programmer’s buffer.
Be sure not to subject the DS1225 to any EPROM programming voltages (by trying to
program the device as an EPROM, for example), since this could be lethal to it.
After reading the DS1225, insert a 2764 EPROM into the programming socket, and program
the EPROM with the buffer’s contents. You now have an EPROM with the same contents
as your NV RAM.
System Requirements
Running BASIC-52 from External Memory
To run BASIC-52 from external memory, your circuit must include the following:
• Any 8052, 8032, 80C52, or 80C32 chip, with pin 31 tied low.
• BASIC-52 stored in non-volatile memory (NVRAM, EEPROM, or EPROM),
beginning at 0 in code memory.
• At least 1K of read/write memory (RAM), beginning at 0 in data memory (required for
all BASIC-52 systems).
• For permanent storage of BASIC-52 programs, non-volatile memory beginning at
8000h in data or code/data memory.
One limitation to running BASIC-52 from external memory is that you can’t use PROG,
FPROG, or PGM. This is because during programming, BASIC-52 accesses the address bus
as ports, but when BASIC-52 runs from external memory, the 8032 needs the address bus
The Microcontroller Idea Book 241