Re: [uCsimm] bogus interrupts on IRQ3?

From: Jason Hihn (jhihn1@umbc.edu)
Date: Mon Sep 03 2001 - 14:32:55 EDT


Why not put the interrupt pulse to a counter, and then just read the counter through PD0-7? Then reset it after the read? that's 16 revolutions you can store in an 8 bit counter with 16 ticks per rev.

9/3/01 10:30:00 AM, daniel.haensse@fhk.usz.ch wrote:

>Did you use ethernet at that time? It is on irq 5!! Maybe if you're working with
>heavy traffic this may be enough to make some pulses missing.
>Try to toggle an output, when the interrupt service routine is executing and
>compare the two traces.
>
>Why don't you use a FPGA to count the pulses? I guess you will run into trouble
>if you have more then 500Hz irq frequency. A FPGA would be easy to
>be read every second to find out the distance. The way to interface the FPGA
>you can find at www.openhardware.net/Dragonix/index.php.
>
>Dani
>
>
>
>Am Mon, 03 Sep 2001 schrieben Sie:
>> Daniel Haensse wrote:
>> >
>> > How many interrupts do you get per second and how is the waveform of the
>> > interrupt signal?
>>
>> Very little interrupts. 16 per wheel revolution, so it depends
>> on how fast I spin the wheel.
>>
>> But even at a pulse per second, I sometimes get spurious interrupts.
>> But only for PD6 (IRQ3), not PD7 (IRQ6)
>>
>> The signal on PD6 and PD7 is a simple blockwave, with sharp edges.
>> The sensor has hysteresis, so no fast hi/lo switches near the
>> transition area.
>>
>>
>> >
>> > Dani
>> >
>> > Am Son, 02 Sep 2001 schrieben Sie:
>> > > Hello,
>> > >
>> > >
>> > > I've written a device driver for my odometer on my robot.
>> > > Basically, it needs to count pulses on PD6 and PD7.
>> > >
>> > > PD6 uses IRQ3,
>> > > PD7 uses IRQ6.
>> > >
>> > > For IRQ3, I sometimes get interrupts, but when checking
>> > > the ISR, the corresponding bit is not set.
>> > >
>> > > Where do these fantom interrupts come from?
>> > > In /proc, I can see:
>> > >
>> > > /proc> cat interrupts
>> > > Internal 68EZ328 interrupts
>> > > 1: 29091 timer
>> > > 2: 603 M68328_UART
>> > > 18: 63 odometer1
>> > > 19: 25 odometer0
>> > > 20: 543 eth0
>> > >
>> > >
>> > > So I do not think that interrupt 18 and 19 are used for anything else.
>> > > IRQ6 looks cleaner: I only get proper interrupts for that one.
>> > >
>> > > Bram
>> > >
>> > > --
>> > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>> > > Bram Stolk "Your mouse has moved. Windows must be restarted for the
>> > > bram.s@chello.nl change to take effect. Reboot now?"
>> > >
>> > >
>> > > This message resent by the ucsimm@uclinux.com list server http://www.uClinux.com/
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>> This message resent by the ucsimm@uclinux.com list server http://www.uClinux.com/
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