Startup ROM

A simple BBC Micro ROM that executes some * commands on startup.

In principle, you could use this for pretty much anything, but I just wrote it as a BBC B/B+ sort-of substitute for the Master's *CONFIG functionality. I can build the ROM image, store it in EEPROM, and have my preferred settings for *FX11, *FX12 and *TV set up on every boot.

Licence

GPL v3 - see COPYING.txt.

Building

This repo contains submodules. Clone it with git clone --recursive, or clone it normally then do git submodule init and git submodule update.

Prerequisites:

• 64tass
• Python 2.x
• GNU make
• Some kind of Unix

Type make. The ROM is built to .build/startup_rom/0/R.STARTUP in the working copy. (Note that .build/startup_rom is a valid volume for BeebLink, if you want quick turnaround when experimenting.)

Choosing commands

To change the commands executed, edit the file commands.txt, putting your own commands in, one per line. Leading *s are optional.

The default configuration runs the following:

*TV255 1
*FX12 2
*FX11 20

Take care if invoking commands from other ROMs - the commands are executed during the ROM initialisation process, and I'm sure many ROMs won't be expecting this :(

Errors at this stage are also not handled particularly gracefully.

Skipping the commands

S+BREAK will cause the startup ROM to do nothing. Anything else (no key, or a key other than S), and it will run the commands.

Showing the commands

Type *HELP STARTUP.

Sideways ROM module

The ROM is perfectly usable just as is, but being <0.5K it's a bit of a waste of a ROM bank. It's therefore intended to be added to another ROM as a relocatable sideways RAM module. (I have it added to a filing system, along with the Tube host code.)

The build process produces a relocatable module: .build/.tmp/startup_module.rom.