Re: Adt(pro)

[David Wilson <mcs6502@gmail.com>]

On Sep 19, 2:16 pm, "Bill Garber" <willy4...@comcast.net> wrote:
> "David Wilson" <mcs6...@gmail.com> wrote in messagebc6ac1d2-ca03-49ea-bb09-02fe018c2bdb@b38g2000prf.googlegroups.com">news:bc6ac1d2-ca03-49ea-bb09-02fe018c2bdb@b38g2000prf.googlegroups.com...
> > The $10 stored in the control reg selects 1 stop, 8 bits, ext rx clk,
> > XTL/16 bps where XTL = 1.8432 MHz so the baud rate is 115200 bps.
> > The $0B is stored in the command reg and selects no parity, no echo,
> > RTS & DTR asserted, no IRQs.
>
> So, uh, can you set an external modem this way?

Yes, but...

1) You will need hardware flow control as the 6551 only has a one byte
input buffer.
2) My Rockwell manual does not show this but I seem to recall that
some (all?) 6551 chips will corrupt the byte currently being sent if
CTS is deasserted mid-character - the 65C51 does not have this
problem.
3) You really need an accelerator card/chip to take advantage of the
higher throughput.