
___________________

ZeriBeep user guide
___________________


User, please note
=================

ZeriBeep is Freeware, i.e. it is free software, but not public domain.

Copyright notice
================

The copyrights (c) of this program belong to John Kortink. All rights are
reserved.

You may not make changes to this program (except for documented configuration
changes). If you distribute it, you may only distribute the complete and
unchanged original copy (as you first received it). You may distribute this
program freely, but must obtain written permission from me if it is to be
distributed as part of, or alongside, any product that is meant to generate
profits. This program is provided 'as is'. Fitness of this program for any
particular purpose is not implied. Using it is entirely at your own risk.


//
//
// Introduction
//
//

ZeriBeep is a module that accurately emulates the SN76489 sound chip, as used
in the Acorn BBC Micro. It runs on Acorn machines running RISC OS 3.1 or later,
and is meant to be used, as supporting software, by BBC emulators and the like.
I use it myself for my port of the Acornsoft game Labyrinth.

Emulation is complete in all respects and, in use, should be close to (if not
exactly like) the real thing. White noise is emulated based on the actual bit
sequence output by the sound chip !

Emulation is at the 'write byte x to chip' level. All emulation beyond that is
taken care of for you. ZeriBeep is basically an 'SN76489 in a module'.


//
//
// Using ZeriBeep
//
//

RMEnsure version 1.05 in your program's !Run file.

When initialising your program, call SWI ZeriBeep_Attach (0x55E40). This
returns the 'write byte' routine address in r0, and the module's workspace
pointer in r1. To write a byte to the SN76489 emulator, call the 'write byte'
routine with the byte value in r0, and the module's workspace pointer in r12.

When closing down your program, call SWI ZeriBeep_Detach (0x55E41).


//
//
// Epilogue
//
//

Updates of ZeriBeep (if any appear) will be made available by (in order of
preference) :

- World Wide Web : visit www.inter.nl.net/users/J.Kortink.
- Electronic mail : email kortink@inter.nl.net.

Enjoy !


John Kortink

