> hm, but what about 57600bps? modems support it, all SW also. > Should I believe that Z8530 can do 38400, 76800 but NOT 57600bps? > With Siemens 82532 serial controller you can do all speeds w/o > any problem (except 76800 of course :)
The Z8530 has no problems with that, but with a clock input of 4.9152MHz as on sparcs you can reach 57600 with 12.5% error, namely with a BRG divider setting of 1. This will give an overall post division by ((1 + 2) * 2) = 6, yielding a bitrate of 4915200 / 16 / 6 = 51200. Compared to that you will get 76800 with a divider setting of 0 like this: ((0 + 2) * 2 = 4, 4915200 / 16 / 4 = 76800. It's not only a problem of speed and fifo depth, but also a problem of integer mathematics. The SAB82532 has an input clock of 29.4912MHz on the Ultras, and also a much more flexible BRG divider section, so it can hit more common baud rates up to B921600 without problems (yes, I tested this). Eddie C. Dost [EMAIL PROTECTED]