<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Bill</div><div><br></div><div>The 8 bit I/O ports on the C64 are based on the MOS Technology 6500 Family parts. The first of these was the 6520 PIA. You can Check <a href="http://www.6502.org/documents/datasheets/mos/">http://www.6502.org/documents/datasheets/mos/</a> for the datasheets. By the time of the C64 I believe they were using the 6522 but I've forgotten. Google is your friend here. </div><div><br></div><div>Btw the 6502 was the most used microprocessor for a very long time. This is different from the most used in new designs (which in thoses days was the Z80). But the be sides being in all the Apple devices and other small personal computers from my favorite (KIM-1) and the C64 it was used in many game decks, arcade equipment and became the definition of the "toaster" processor during the C standards meetings because it was hidden in so many things. </div><div><br></div><div>Clem<br><br>Sent from my iPhone</div><div><br>On Jun 27, 2015, at 8:59 PM, Bill Cunningham <<a href="mailto:billcun@suddenlink.net">billcun@suddenlink.net</a>> wrote:<br><br></div><blockquote type="cite"><div>
<meta content="text/html; charset=iso-8859-1" http-equiv="Content-Type">
<meta name="GENERATOR" content="MSHTML 8.00.6001.18702">
<style></style>
<div><font size="2" face="Arial"> I am looking at this
page...</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial"><a href="http://www.mikroe.com/chapters/view/4/chapter-3-i-o-ports/">http://www.mikroe.com/chapters/view/4/chapter-3-i-o-ports/</a></font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Now would this be similar or what the C64 MOS
processor would be like? The specs I got ahold of says "8 bit bidirectional IO
ports" I don't know who is familiar with the commodore 64s. But it's something
to think about. I was also ready the APIs IO functions in simh.doc.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial"> One thing in C I haven't got to
is this idea of function return types being in parenthesis. What's that for? I
have seen it several times.</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Bill</font></div>
<div> </div>
</div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Simh mailing list</span><br><span><a href="mailto:Simh@trailing-edge.com">Simh@trailing-edge.com</a></span><br><span><a href="http://mailman.trailing-edge.com/mailman/listinfo/simh">http://mailman.trailing-edge.com/mailman/listinfo/simh</a></span></div></blockquote></body></html>