Multitech MPF-I/88

How to write a Hello World application for MPF-I/88 from scratch:

You can write assembly directly on the MPF-I/88 using line assembler A directve but it's awkward and not too exciting.
Instead, set up a proper toolchain: write the code on your computer and upload it via tape interface.

1. Write code:

Here is an example of Hello World application.
Remember that RAM area below 0080:0000 is used for system variables.
CS default value is set to 0x0080 by MPF-I/88 so, considering that maximum RAM size is 24kB, you will hardly need to change it.
Base your code at ORG 0h and it should work fine.

2. Compile:

Use any suitable i8088 assembler that can generate absolute code.
I have used Microsoft Macro Assembler v6.11 inside the DOSBox.

3. Convert binary output file to audio file:

I have written a simple C program to generate the audio file from binary data.
Here is the audio file using classic square waveform or bandwidth-limited continuous phase sinewaves - in case you are going to broadcast it over CB radio.

4. Upload audio file to MPF-I/88:

Connect audio output of your computer to 'EAR' socket of the MPF-I/88.
Type R at command prompt.
Play the file.
You should see READ FILE:FILENAME on the console after the tape header has been successfully read.
After the rest of the file finished loading you will get the ">" prompt back.
Type G if your code starts from the default 0080:0000 address.

5. Observe the results and update your CV with a new skillset.

Multitech MPF-I/88 User Manual

Multitech MPF-I/88 Reference Manual

Multitech MPF-I/88 Monitor Program Source Listing

Multitech MPF-I/88 Schematic:

Sheet 1 of 5
Sheet 2 of 5
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Sheet 5 of 5

Main PCB scan - bottom side