Burning an EPROM with the SSM PB1

This machine has an SSM PB1 2708/2716 EPROM programmer board and the programmer software from the PB1 manual. You put data in memory and run the burner. After that, you save the burned chip as an Intel HEX file on your host.

cd examples/pb1
altairsim pb1.toml

The machine starts the SSM 8080 System Monitor and prints:

MONITOR V1.0
.

The . is the prompt of the SSM monitor. Press Ctrl-E to go to the altairsim> prompt. Type RUN to go back to the SSM monitor.

The machine

The machine is a plain Altair with these parts:

• An 8080 processor, 52K of RAM at 0000-CFFF, and the front panel.
• An SSM IO-4 board at ports 00-05. Its serial port A is the console.
• The PB1 board. Its control port is 10H. Its 4K programming-socket window is at D000.
• The SSM 8080 System Monitor in a ROM at F000.

The PB1 software is written for the SSM monitor, and it uses these fixed addresses: control port 10H and socket window D000. RAM stops at CFFF so that the window is not RAM.

The four programs

These routines are from the PB1 manual (copyright Solid State Music, 1978). The source and the Intel HEX files are the same as in the manual.

The SSM monitor at F021

Each program ends with JMP F021H. The two check programs also CALL F009H. Section 3.3 of the PB1 manual gives the reason. F021 is the entry address of the SSM monitor. F009 is its console-output routine. The machine has the SSM monitor at F000, so the programs run as SSM wrote them:

• A burner returns to the SSM monitor when the burn is complete. The monitor prints its banner and its . prompt again.
• A check program prints P (pass) or F (fail) and then returns to the SSM monitor.

To use the programs with a different monitor, change two things. Change the address bytes at 011F and 0120 for the exit. Change the CO equate for console output.

Burn a 2708 and make a HEX file

Start the programs with the G (go) command of the SSM monitor.

1. Press Ctrl-E.
2. Put 1K of data at 4000, and load the three programs. They have different origins, so all three stay in memory:

altairsim> FILL 4000-43FF A5 ; or LOAD your-data.hex: the 1K to burn, at 4000 altairsim> LOAD PROG2708.HEX ; the SSM 2708 burner (manual §4.2) altairsim> LOAD ERACHK.HEX ; the erase check (manual §4.4) altairsim> LOAD CPYVFY.HEX ; the verify (manual §4.5) altairsim> RUN ; back to the SSM monitor

3. Type G140 and press Enter. The program checks that the chip is erased:

G140 P MONITOR V1.0 .

4. Type G100 and press Enter. The burner prints nothing. The burn is complete when the prompt comes back:

``` G100

MONITOR V1.0 . ```

5. Type G180 and press Enter. The program compares the chip with the data at 4000:

G180 P MONITOR V1.0 .

6. Press Ctrl-E. Save the socket window to a file on your host:

altairsim> SAVE eprom.hex D000-D3FF ; the burned 2708, as an Intel HEX file

eprom.hex is an Intel HEX file. After the burn, the socket window is memory that you can read. SAVE reads it from the bus and writes the HEX file. The board does not write files.

Now the chip is not erased. If you run the erase check (G140) again, it prints F.

For a 2716, load PROG2716.HEX in place of PROG2708.HEX. Burn 2K from 4000-47FF, and save the 2K window D000-D7FF. The two check programs are for the 1K 2708. To check a 2716, change the 03 at the start of the program to 07, as the source files show.

The board is documented in the altairsim User Manual.