Re: Mockingboard output through IIgs internal speaker?

[Roger Johnstone <roger@ihug.invalid>]

In <e2.32.uS2SC5JU1na7Ghb.NR@aqu.candybar.ne.jp> Hidehiko Ogata wrote:
> Roger Johnstone wrote:
> 
>> Because double hi-res really has two modes: 560 pixels per line in
>> monochrome and 140 pixels per line in colour. The older computers had 
>> no way of telling which mode you wanted, so the IIe composite colour
>> monitor has a switch on the front to turn off colour! The IIgs 
>> replaces that with a softswitch.
> 
> Hmm, care to note the address?

It's bit 5 of the New-Video Register at $C029. Set it to 0 for DHR 
colour, 1 for DHR monochrome. The other bits in the register are used 
for other functions, so always change the bit with a read-modify-write 
instruction sequence, and when your program is finished it should of 
course set the bit back to its original value.

-- 
Roger Johnstone, Invercargill, New Zealand

PS/2 Mouse Adapter for vintage Apple II or Mac
order at http://vintageware.orcon.net.nz