Path: utzoo!attcan!uunet!cbmvax!fred
From: fred@cbmvax.UUCP (Fred Bowen)
Newsgroups: comp.sys.cbm
Subject: Re: Rs-232 standard?
Keywords: Rs-232 UART
Message-ID: <5818@cbmvax.UUCP>
Date: 26 Jan 89 20:47:10 GMT
References: <2471@nunki.usc.edu>
Reply-To: fred@cbmvax.UUCP (Fred Bowen)
Organization: Commodore Technology, West Chester, PA
Lines: 20

In article <2471@nunki.usc.edu> aliu@nunki.usc.edu (Lord Bane) writes:
>How does the Rs-232 standard is implemented in the Commodore?
>What is the Rs-232 standard?
>What's the difference between the Standard Rs232 and Commodores Rs232
>(Besides the obvious voltage levels)?
>Commodore wanted to keep the Configuration register compatible with
>the UART chip.  What is this UART?

The C64/128 kernel implements the RS-232 interface via software, via the
user (parallel) user port.  The rest of the typical RS-232 lines (RTS, CTS,
DTR, DSR) are implemented only if the channel is configured for x-line (as
opposed to 3-line) mode.  The C64/128 Programmer's Reference Manuals describe
this in detail.  The "UART" emulated is a 6551.
--
-- 
Fred Bowen			uucp:	{uunet|rutgers|pyramid}!cbmvax!fred
				arpa:	cbmvax!fred@uunet.uu.net
				tele:	215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380