Date   : Wed, 01 May 2002 10:08:55 +0100 (BST)
From   : Sprow <rsprowso@...>
Subject: Re: BBC joystick code

On Tue, 30 Apr 2002, Nic Bwts wrote:

> hello
> I have been searching the web for people who used to program BBC micros
because I 
> am looking for an example of some assembley code that makes use of joysticks.
To be 
> more precise I am looking for examples of code that make use of the analogue
to digital 
> coverter interupt routine. I have read the user guides but they give no
examples of the 
> code needed to do this. I hope you can help as I have been searching for
two months 
> now (not continuosly I do have other thing to fill my time honestly).

Sounds like a copy of the Advanced User guide is required.
As an overview,you need to change the system VIA interrupt "AND" mask
(some high numbered OSByte does this) so that the OS doesn't see
interrupts from the ADC.

The conversion completion interrupt will then pass through IRQ2V,and armed
with a copy of the 7002 datasheet,you should have everything you need.

Alternatively (less talking to the hardware) you could make use of the
"ADC conversion complete event" and get the OS to talk to the hardware for
you,
Sprow.