On 9/4/2018 2:09 PM, smf wrote: > 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. > > > It works as designed. /16 mode gives 115200. The T232 used this to get 115200 and 230400 (by using the 6551A and double clocking it) JIm -- Jim Brain brain@jbrain.com www.jbrain.comReceived on 2018-09-05 03:00:07
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