From: "Paul Fulghum" <paulkf@microgate.com>
To: "Geir Thomassen" <geirt@powertech.no>,
"Theodore Tso" <tytso@mit.edu>, <linux-kernel@vger.kernel.org>
Subject: Re: Serial port latency
Date: Thu, 22 Mar 2001 14:55:38 -0600 [thread overview]
Message-ID: <00b101c0b312$7385ddb0$0c00a8c0@diemos> (raw)
In-Reply-To: <3ABA42A8.A806D0E7@powertech.no> <20010322140852.A4110@think> <3ABA6167.309E6DB2@powertech.no>
> The serial port chip is 16550A, which has a built in fifo. Can this be
> the source of my problems ?
>
> Geir
I thought about that. If the number of receive bytes in the RX FIFO
is less that the trigger level then a timeout has to occur before
getting the next receive data interrupt.
The 16550AF data book says that this timeout is 4 characters
from when the last byte is received. This is a maximum of 160ms
at 300bps (when using 12bit characters: 1 start + 8 data + parity + 2 stop).
So this would be smaller at 9600 and could not account
for the 500ms delay.
Paul Fulghum paulkf@microgate.com
Microgate Corporation www.microgate.com
next prev parent reply other threads:[~2001-03-22 20:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-22 18:21 Serial port latency Geir Thomassen
2001-03-22 20:08 ` Theodore Tso
2001-03-22 20:32 ` Geir Thomassen
2001-03-22 20:55 ` Paul Fulghum [this message]
2001-03-22 22:44 ` Theodore Tso
[not found] ` <20010322141937.C22479@universal-fasteners.com>
2001-03-22 21:02 ` Geir Thomassen
2001-03-22 21:52 ` Jonathan Lundell
2001-03-22 23:25 ` Pavel Machek
2001-03-23 14:43 ` Geir Thomassen
[not found] <Pine.LNX.4.20.0103221219410.3343-100000@linuxtaj.korpivaara.org>
2001-03-22 20:03 ` Geir Thomassen
2001-03-22 20:17 ` Trent Jarvi
-- strict thread matches above, loose matches on Subject: below --
2001-03-22 21:45 Manfred Spraul
[not found] <000401c0b319517fea9@local>
2001-03-25 23:10 ` Pavel Machek
2001-03-29 7:58 ` Manfred Spraul
2001-03-30 22:36 ` Pavel Machek
2001-03-31 22:09 ` Manfred Spraul
2001-04-10 0:37 ` Andrea Arcangeli
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