AW: C64 Keyboard Scanning

From: Spiro Trikaliotis (Spiro.Trikaliotis_at_gmx.de)
Date: 2000-10-10 09:50:18

Hello Nicholas,

> how does the C64 kernal scan the keys - does it strobe column
> by column (pa0
> - pa7, one by one) and read the answer in pb0 - pb7; or does it set all
> columns at once?

BOTH!

At first, it sets all rows, testing if there is any key pressed. If not,
that's all. If one was pressed, the kernal tests the  rows one by one to
identify the key. But it does not use any other combination (2..7 rows at
once).

HTH,
   Spiro.

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