Re: [stella] Space Savers

Subject: Re: [stella] Space Savers
From: "Alex Herbert" <herbs64@xxxxxxxxxxx>
Date: Tue, 7 Sep 2004 19:53:51 +0100
----- Original Message ----- 
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
To: <stella@xxxxxxxxxxxxxxxxxx>
Sent: Friday, September 03, 2004 8:33 PM
Subject: Re: [stella] Space Savers

> That depends on how quickly you can swap your game cartridges
> and if you ever play any games that do send data through the
> RIOT ports, like the keyboard games. ;-) While the 6507 will
> be reset at power-up, the RIOT will not. It will remain it's
> state for a short while after you turn the console off.

The RIOT uses the same reset line as the CPU and is reset at power on, and
to quote the datasheet, "... a low /RES input causes a zeroing of all four
I/O registers.  This in trun causes all I/O busses to act as inputs thus
protecting external components from possible damage and erroneous data while
the system is being configured under software control."

So there shouldn't be any need to initialize the ports at boot unless you
need outputs.

Alex Herbert

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