From: utzoo!decvax!cca!lee@Utexas-11@sri-unix
Newsgroups: net.micro
Title: Reply to: 6850 sio acia
Article-I.D.: sri-unix.3294
Posted: Wed Sep 15 23:27:51 1982
Received: Thu Sep 16 03:52:12 1982

From: Bill Lee 
What you need is a Motorola microcomputer components guide. It will
tell you everything you need to know about the 6850 as well as other
Motorola components that you may be using. 03H is Master Reset.
8 bit/no parity/ 1 stop bit is 14H. 8 bits/even parity/1 stop bit is 018H.
Odd parity is 01CH (these are bits 2, 3, and 4). Bits 5 and 6 are
Transmitter Control Bits which control transmitter interrupts
depending on RTS. The high bit (bit 7) is Receive Interrupt Enable.
And finally, the bottom 2 bits are Counter Divide Select. 01H is
divide by 16. What you were sending with 91H was Receive Interrupt
Enable, RTS=low, transmittinginterrupt disabled, 8 bits plus 2 stop bits,
and divide the clock by 16. What you may want to be putting in the
control register is 15H. As you can see this gets very complicated
and you should probably have a data sheet to see what you are doing.
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