Message-ID:	<38A71683.49D04557@online.de>
Date:	Sun, 13 Feb 2000 21:39:31 +0100
From:	Gero Timann <geti AT online DOT de>
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Timer Interrupt Routine
References:	<885sgn$m27$1 AT ac1 DOT ewetel DOT de>
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

Hello,

What's about using the other PC-Timer, the Realtime-Clock, at int 0x70
(CPU-View) - 0x8 (PIC-View). If you need some code-snipsets, send
me a mail.

Yours,
   Gero

Thorsten Erdmann wrote:

> Hi,
>
> I have a little bit tricky problem. I want to pass data from a file to a
> special hardware in the background. I have to poll the hardware, if it says
> ready I transfer a byte. I want to do this via a timer subroutine. The
> problem is the file access. Because the files are very big I cannot load
> them completely to RAM. So I think of using a buffer, lets say 16kB. The
> Timer ISR gets a byte from the buffer and sends it to the hardware device.
> When the buffer is nearly empty it triggers a second routine which loads new
> data from file to the buffer.
>
> The problem is that this second routine runs much more longer that the timer
> interval, so it cannot be an Timer-ISR, too. How can I trigger this routine,
> without using a polling loop in the main program. It is no problem that the
> main program gets interrupted during running of that disk routine, but I
> don't want to do anything special during the main program to check if there
> is data needed.
>
> Do you understand the problem? What can I do ?
> In assembler I would manipulate the stack, so the ISR "returnes" to the disk
> routine, that one then returns to the main program. How can I do that in
> plain C.
>
> Thanks
> Thorsten

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