Search found 819 matches

by Twilighte
Sat Jan 21, 2006 2:50 pm
Forum: AY sound chip
Topic: AY Crudentials: Samples Overview
Replies: 0
Views: 6356

AY Crudentials: Samples Overview

Playing a sample on the Oric may appear a daunting task, since the sound chip is not memory mapped and their is a big difference in resolution between samples played on the PC and Oric. A Sample is a sequence of values sent to an Amplitude register in quick succession where each value was taken from...
by Twilighte
Sat Jan 21, 2006 2:19 pm
Forum: AY sound chip
Topic: AY Crudentials: 8 Bit Samples
Replies: 4
Views: 10816

AY Crudentials: 8 Bit Samples

The hardware of the Ay-3-8912 can only handle up to 4 bit resolution but may handle up to 8 bit through the mixing of the 3 available channels. A phenomenon exists that means that when the volume of channel A is set to one value, and the volume of channel B is set to another, the effective single ou...
by Twilighte
Fri Jan 20, 2006 10:14 pm
Forum: AY sound chip
Topic: AY Crudentials: Making all AY registers Visible in Memory
Replies: 0
Views: 6628

AY Crudentials: Making all AY registers Visible in Memory

This follows on from "AY Crudentials: Accessing the AY". To make all AY registers visible in main memory, we can write a simple AY Register Dump Routine. Note: this routine actually already exists in BASIC 1.1 ROM but does not compensate for special case Register 0D. The routine uses two tables. Tab...
by Twilighte
Fri Jan 20, 2006 9:58 pm
Forum: AY sound chip
Topic: AY Crudentials: Accessing the AY
Replies: 3
Views: 9853

AY Crudentials: Accessing the AY

The AY-3-8912 is not memory mapped in the Oric and the method of accessing it is obscure (to say the least). However, with a little knowledge, it is easy enough to write and read from any register. The AY-3-8912 is linked to the system by the way of one data/register port and 2 control lines. The co...
by Twilighte
Thu Jan 19, 2006 1:24 pm
Forum: AY sound chip
Topic: AY Crudentials: The Envelope Generator
Replies: 0
Views: 7085

AY Crudentials: The Envelope Generator

The AY-8912 Sound chip that lurks within the depths of the Oric has a little used Envelope Generator. An Envelope Generator controls the volume of a selected channel outside of processor intervention. This means that once initiated, it will continue without any other action by the user/processor. Ho...
by Twilighte
Wed Jan 18, 2006 7:12 pm
Forum: Audio tools
Topic: Sound Effects using Sonix (overview)
Replies: 4
Views: 11233

no, i did too.
Steve Marshall also did (he produced at least two pieces of music) but since his background is in Music, he always would have preferred a stave system.
by Twilighte
Mon Jan 16, 2006 4:01 pm
Forum: Audio tools
Topic: Sound Effects using Sonix (overview)
Replies: 4
Views: 11233

Sound Effects using Sonix (overview)

Sound Effects have traditionally been a subset of a music player, where instead of a group of patterns playing a song, a single pattern or note is used with the traditional Volume sequence (Sample in Sonix) and ornament (for controlling relative pitch/note). Sound Effects tend to be limited to a sin...
by Twilighte
Thu Jan 12, 2006 12:32 pm
Forum: Painting tricks
Topic: Embedded Masked Graphics
Replies: 1
Views: 8515

mask_table and bitmap_table are two 256 byte tables used to optimise the plot routine. Code may be adjusted not to use these tables if memory is tight. The existing routine was... lda (Graphic),y tax lda (background),y and mask_table,x ora bitmap_table,x sta (background),y with no bitmap table... ld...
by Twilighte
Thu Jan 12, 2006 12:13 pm
Forum: Painting tricks
Topic: Embedded Masked Graphics
Replies: 1
Views: 8515

Embedded Masked Graphics

Masking is a technique used on most computer graphic engines to highlight certain objects from other objects they may overlap especially when dealing with few colours. Like showing a monochrome hero sprite over of a complex monochrome background. Unless the sprite is perfectly square, a mask cannot ...