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List:       linux-rt
Subject:    [rtl] Re: HW interrupt/NI Board
From:       Gray Abbott <gray () sofgry ! com>
Date:       1999-01-28 3:44:54
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Rob Butera wrote:
> 
> Hi folks - I have an IRQ question.
> 
> My RTLinux application has been debugged and is running great.  However, I
> am currently using the RTC to generate my hardware interrupt, and want to
> use my NI AT-MIO-16E-1 board to generated an interrupt at a faster rate.
> ...
> 2) if anyone has any experience register-level programming a National
> Instruments board, I remember some comments in someone's source code
> (comedi?) about some inconsistent IRQ specifications (specifying in the PNP
> configuration versus writing to the appropriate registers) with NI
> boards, but I can no longer find that info.  I'd be happy to share
> the details of what registers I've configured to people who know these
> things ...

I'm pretty sure that the PNP settings for the IRQ have no effect.  You need to do the \
PNP setup so that the I/O ports are mapped (so you can address the board), but I \
believe the IRQ and DMA settings are ignored. 

To select interrupts, you have to map the DAQ-STC interrupt to an ISA bus interrupt \
in your board setup (i.e. with register programming).  You select the ISA bus \
interrupt with a three-bit code in the Interrupt_Control_Register.  The values, 0-7, \
map onto ISA interrupts 3,4,5,7,10,11,12,15, in order.  (You also have to set the \
interrupt enable in that same register.)  

This mapping is not explained in the documentation, so it wouldn't surprise me if \
that's keeping your interrupts from working.  (In fact, the list may still be wrong;  \
I seem to recall that some of those IRQ numbers never worked for me.  But NatInst did \
confirm the list, above...)

If you need some example code, let me know.  I can send you a working driver and \
application library.

-- 

Gray Abbott (gray@sofgry.com)       http://www.sofgry.com/Sofgry/
Sofgry Systems                      ** Austin Technical Events Calendar:
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