Re: strange read with a 6502...

From: A. Fachat <*afachat_at_gmx.de*> Date: Wed, 30 Mar 2016 10:37:06 +0200 Message-ID: <153c6ab4350.279a.b4d1f2b66006003a6acd9b1a7b71c3b1@gmx.de> · afachat_at_gmx.de

Am 30. März 2016 10:15:24 schrieb didier derny <didier@aida.org>:

> I have a problem with a read with a 6502
>
> I read a data on a register (from a CH376S)
>
> I have the following code:
>
>                      *= 2000
> readdata      LDA    CH376data
>                       RTS
>
>
> this code always get  the wrong value
>
>                      *= 2001
> readdata     LDA    CH376data
>                       RTS
>
>
> now with this code I get the right value...

That could be a broken address line to the IO chip or a timing issue in the 
address decode depending on the addresses.

André

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