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Nik,<br>
<br>
If you are building a custom ROM, then you have probably turned off
"Auto Flow Control." It doesn't exist on the 8250, 8250A, or 8250B;
and it is broken in the TL16C550C DIP version. Wayne reports to me
that it works in the TL16C550C PLCC version, used on the MF/PIC
board.<br>
<br>
--John<br>
<br>
<br>
<br>
<br>
On 05/27/2013 05:13 PM, brizza wrote:
<blockquote
cite="mid:e779e7a3-1781-4450-a058-73c1eff93cf9-/***@public.gmane.org"
type="cite">Hi John,
<div>Yes there are two seperate issues now. But as far as the
Hazeltine goes, Yes it works with all of the previous BIOS
flavors ie DW, DG and Andrew's default ROM. So from that i'm
guessing the right signals are all present. I will however build
another cable that includes the other signals if it helps with
the</div>
<div>WDW BIOS, just waiting for the RS232 test dongle to arrive.</div>
<div>Thanks again,</div>
<div>Nik</div>
<div><br>
<br>
On Tuesday, May 28, 2013 10:00:23 AM UTC+10, John Coffman wrote:
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000"> Nik,<br>
<br>
The discussion has become so involved that I have a question
that may be redundant: do you have the Hazletine working
with any CPU board of the N8VEM flavor?<br>
<br>
The problem sounds more and more like an RS-232
communication problem, likely resolvable with a custom-wired
null modem cable. My guess is that the Hazletine will not
send from the keyboard because it is not seeing the
combination of RS-232 control signals that it requires.<br>
<br>
The SBC v1 puts out only 2 signals:<br>
<br>
TXD crossed to RXD in the
null modem cable<br>
/DTR probably crossed to /DSR in the null
modem cable<br>
<br>
The SBC v1 does not put out /RTS or /CD. /RTS would cross
to /CTS in a null modem cable.<br>
<br>
It is entirely possible that the Hazletine is looking for
one or more of the following:<br>
<br>
/DSR (6) pin numbers for the
25-pin RS-232 connector<br>
/CD (8)<br>
/CTS (5)<br>
<br>
My Wyse-30 terminal requires all 3 of the above. In other
words, at the 25-pin connector on the back of the Wyse,<br>
in the idle state, pins:<br>
<br>
1,7 ground<br>
2,3 < -3v<br>
4,5,6,8,20 > +3v<br>
<br>
--John<br>
<br>
<br>
<br>
<br>
<br>
On 05/27/2013 04:39 PM, brizza wrote:
<blockquote type="cite">Hi Wayne,
<div>Running at 4MHZ made no change. I have tried
replacing the RAM chip also.</div>
<div>I have ordering a couple of 16C550C's to replace the
8250 and some larger eproms (27C080) to replace the
27C040's .</div>
<div>In the meantime i'll try and get my SBC V2 working.</div>
<div>Thanks to all for your tireless efforts of help :-)</div>
<div>Nik</div>
<div><br>
</div>
<div>On Tuesday, May 28, 2013 7:52:15 AM UTC+10, Wayne
Warthen wrote:
<blockquote class="gmail_quote" style="margin: 0pt 0pt
0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">Thanks Oscar.
<div><br>
</div>
<div>Nik, based on the fact that both Oscar and Max
are running a slower CPU clock, I definitely think
it would be good if you could try a slower clock
speed if you can.</div>
<div><br>
</div>
<div>If a slower cpu clock seems to fix things, I will
look at options for conditionally adding some delays
after bank switches.</div>
<div><br>
</div>
<div>Thanks,</div>
<div><br>
</div>
<div>Wayne<br>
<br>
On Monday, May 27, 2013 12:56:09 PM UTC-7, oscarv
wrote:
<blockquote class="gmail_quote" style="margin: 0pt
0pt 0pt 0.8ex; border-left: 1px solid rgb(204,
204, 204); padding-left: 1ex;">Wayne,<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin: 0pt
0pt 0pt 0.8ex; border-left: 1px solid rgb(204,
204, 204); padding-left: 1ex;">
<p>What speed is your SBC running?</p>
</blockquote>
<div>That may confirm your suspicion: a slow 4Mhz.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin: 0pt
0pt 0pt 0.8ex; border-left: 1px solid rgb(204,
204, 204); padding-left: 1ex;">
<p>If convenient, perhaps you could extract
NAVEM_std.com</p>
</blockquote>
<div>I'll have a go, but it'll take a week to
report back as I'm away from home alas.</div>
<div><br>
</div>
<div>Regards,</div>
<div><br>
</div>
<div>Oscar.</div>
<div><br>
</div>
</blockquote>
</div>
</blockquote>
</div>
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