[Coco] Assembly code scans keyboard but doesn't repeat

Mark McDougall msmcdoug at iinet.net.au
Mon Mar 6 18:22:14 EST 2017


On 7/03/2017 9:28 AM, Glen Hewlett wrote:

If you save the previous column scan byte, and then XOR it with the new 
column scan byte, then any change of state will be indicated by a '1' 
bit in the result. If you then AND that with the complement of the new 
byte, then a '1' bit means the key has just been pressed (aka 
rising-edge detect).

At least that works in my head right now. ;)

Regards,

-- 
Mark McDougall
<http://retroports.blogspot.com.au>


More information about the Coco mailing list