Re: 6510 and 8500 differences

From: Richard Atkinson (Richard.Atkinson_at_cl.cam.ac.uk)
Date: 2000-07-28 01:32:19

On Thu, 27 Jul 2000, Nicolas Welte wrote:

> Since I was not sure of that anymore, I did a few quick tests on a 8500
> and a 6510 with a few peek and poke commands. The results are as
> follows:
> 
> - both the 6510 and 8500 have a full featured 8bit data direction
> register at $00. 
> - bits 6 and 7 of $01 will always return 0 on reads if their
> corresponding bits are set to 0 (input) in $00
> - bits 6 and 7 of $01 will return 1 for a certain time after writing
> this value if set to output via $01
> - this time varies between the 6510 and 8500 due to their different
> nature (NMOS/HMOS). The 6510 will retain the value not as long as the
> 8500. This is probably a matter of micro to milliseconds (6510) vs
> several seconds (8500). 

Brilliant, Nicolas! I'll see that this functionality finds its way into
LUnix.

I must admit, I really didn't think it would be possible to detect between
6510 and 8500. cbm-hackers does it again! This is why CBM machines are so
satisfying to hack.


Richard

-- 
Richard Atkinson
Software Engineer
Tenison Technology EDA Ltd
http://www.tenisontech.com/

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