On 9/4/2018 11:34 AM, Gerrit Heitsch wrote: > On 09/03/2018 10:08 PM, Mia Magnusson wrote: >> >> The A2232 7-port serial card for Amiga uses the 6551 and it seems to >> think that CTS and DCD is really broken and uses a separate 8520 CIA >> instead of the 6551's for those signals. >> >> Btw this is probably well known but there is an alternative driver >> available on Aminet which afaik is a complete rewrite, making that card >> able to run at 115200 on it's fist two ports with no data loss and >> almost no cpu load on the Amiga. > > Back then I recommended a hardware hack... Bend then XTAL-Pins of the > 8551 or 6551 from the Socket and solder a 3.6864 MHz crystal to it. > Yes, that was overclocking the chip, but this way you were able to get > 38400 on one or two ports without any changes to the software. You > just needed to remember that real baudrate would be double of what you > selected in the software. > > Gerrit > > If folks are interested, I created a "daughtercard" for the 6551/8551 that allows the X551 to configure for bos rates 230K, 115.2K, 57.6K, 38.4K, and the original speeds. It sits in the X551 socket and the X551 sits on the unit. It requires no flying leads and is configured using the same registers as the original X551. Jim -- Jim Brain brain@jbrain.com www.jbrain.comReceived on 2018-09-04 19:02:52
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