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Subject: Re: transmit on remote pin with sci?

Re: transmit on remote pin with sci?

From: sophana <>
Date: Sun, 2 May 2004 23:12:59 +0200

I've looked at the patch
the tx routine is polling the timer.
this means that it must not be called from an interrupt routine...
my problem is that with the unilink protocol, the PIC polls the rockbox
during an 8ms window.

during these 8ms, the pic sends a polling char then listen until the end of
the 8ms.

How frequent is the remote_control_rx routine called? (max latency)
if I want to send about 20 bytes, at about 57600, it takes about 3.5ms

what is the max latency for the polling request to be responded?
if it is called every 1ms, it should work

Too bad I finished my own implementation...
I think I will use the patch...

Will it be merged into cvs oneday?

"[IDC]Dragon" <> a écrit dans le message de
> I'm trying to implement a transmit interrupt handler
> everythin seems ok but I have nothing on the serial line...
> Is Txd1 also connected to the serial pin?


> If not, do I have to transmit with the rxd1 pin as IO?

Yes, and in an "open drain" fashion to avoid collisions. Never pull high,
either let float or drive low.

> has anybody implemented it as interrupts? how fast can it go ? (I would
> like to reach 19200 or 57600...)

Yes, has been done. High baudrates (up to 115k tested, iirc) are possible.
Credits go to Dirk-Andreas, not me. By popular demand I've just uploaded his
latest patch into the tracker, without further verifying


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Received on 2004-05-02

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