Re: Plus/4 RS232 woes

From: smf <smf_at_null.net>
Date: Tue, 4 Sep 2018 20:09:14 +0100
Message-ID: <e64cc7c9-a038-0b2a-7c2b-e784218e3895@null.net>
On 04/09/2018 18:32, Mia Magnusson wrote:
> But then I found that driver on Aminet and it worked far better, and I
> installed the original crystal instead and used 115200.

This is from memory when I added support for this to mame as some apple 
3 software used it.

The 6551 can work from an external crystal (XTAL1/XTAL2) to drive an on 
board clock generator for asynchronous or an external TxC (XTAL1) for 
synchronous comms.

However if you turn off the on board clock generator then the 1.8mhz 
crystal gets divided down by 16 and you get 115200.

I have no idea if the chip designer would have a fit or not, it's 
certainly not clear from the documentation that it should work at all.
Received on 2018-09-04 22:00:06

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