Date   : Thu, 05 Jul 1984 06:10:40-PDT (Thu)
From   : ihnp4!mgnetp!burl!pmh@Ucb-Vax.arpa
Subject: National 8250 initialization routine needed

--
Well, I've gotten the terminal emulator to work on my h-89, but I'm
still having problems with my downloading routine. Is there anyone
out there who can verify that I'm setting my I/O up correctly? I
have my modem on a port that I have initialized for 8 bits no parity
at 300 baud. I am not using an interrupt driven routine so the
interrupt enable register is zeroed out. To determine if data is
present I test the DATA READY bit in the line status register. I
guess what I really need (assuming all the previously mentioned
parameters are correct) is for someone to explain the Christiansen
Protocol. I am able to retrieve 1 record of data from an RCPM, but
subsequent records get trashed. HELP!! What I need to know is:
       1. What is the actual length of each transfer (including
          checksum, etc)?
       2. What handshaking signals are necessary and when?
       3. Any other pertinent info.
Presently, to start the transfer, I send a NAK and after each 128
byte record received, I send an ACK. I've set up the software to
return the RCPM's EOT with one of it's own. 
If anyone has a working modem program on a Heath H-89, please let me
know. I'll mail you a disk if you can copy it for me. I'd like to
get my program running, but that's not the foremost consideration if
I can procure an already operating one. My dilemma is that <gasp>
I'm still using hard-sectored disks. I've had people offer me stuff
in the past, but alas, my machine can't read it because they only
use sft sectored disks. Again HELP!
Thanks in advance.
-- 
>From the non-linear mind of a non-anonymous hacker!!
                               Pete Hermsen
ihnp4! \                       PO Box 2304
akgua!  \burl!pmh              Burlington, NC 27216
cornell! /                     (919) 228-4215 (w)
ulysses!/

"Not all roads lead to Hollywood..."