15 Apr
2005
15 Apr
'05
7:18 p.m.
Subject: 7201 (was Re: Z8530 (was Re: Navtel 9460
Protocol Analyzer info?))
From: "Eric Smith" <eric at brouhaha.com>
That chip sucked when used as a plain old UART. In
order to handle slight
speed mismatches between two modems emplying synchronous modulation,
;-) It was nearly a full clone of the Z80 SIO with one difference,
the interrupt logic matched the 8085/8086 rather than Z80.
As a simple SIO it was a major pita to use, too dang many registers.
As a result I ahve a bunch of them and never use them. Ise the 2681,
8251 or 8250 before that beastie.
The only thing worse to design with and use was the COM2501, dumb
as a stump.
Allison
15 Apr
15 Apr
10:20 p.m.
New subject: 7201 (was Re: Z8530 (was Re: Navtel 9460 Protocol Analyzer info?))
On 4/15/05, Allison <ajp166 at bellatlantic.net> wrote:
The only thing worse to design with and use was the
COM2501, dumb
as a stump.
Heh... we used the COM5025 for our Unibus COMBOARDs (before we
switched to the Z8530). _The_ reason was that it was the sync serial
chip on the Qbus board (DPV11?) for our earlier protocol box that was,
in effect, an entire PDP-11 that hung off of a larger host -11 and did
HASP and 3780 front-end work. They went with the same serial chip to
simplify the porting effort (the first cut of the code was converted
from MACRO-11 to 68K assembly by a TECO macro).
I have *hundreds* of COM5025 chips on the shelf here. Never found a
use for them.
-ethan
16 Apr
16 Apr
1:24 a.m.
On Fri, 15 Apr 2005, Allison wrote:
As a result I ahve a bunch of them and never use them.
Ise the 2681,
8251 or 8250 before that beastie.
8251! Now there's a turkey! At least it was simple. One of the
buggiest pieces of crap I ever had to initialize.
The only thing worse to design with and use was the
COM2501, dumb
as a stump.
Serial chips, I get post-traumatic-stress just thinking about
them.
9:46 a.m.
At 12:24 AM 4/16/2005, Tom Jennings wrote:
And reading the manual of Chuck Forsberg's Pro-YAM, I always
had the impression that's what happened to him, too.
- John
The only thing
worse to design with and use was the COM2501, dumb
as a stump.
Serial chips, I get post-traumatic-stress just thinking about
them.
7033
days inactive
7034
days old
3 comments
4 participants
participants (4)
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ajp166＠bellatlantic.net -
ethan.dicks＠gmail.com -
jfoust＠threedee.com -
tomj＠wps.com