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GPIO interrupts in DSP56F827

Started by atid2 November 19, 2002
Hi,

I am trying to use the GPIO interrupt mechanism but I have a problem:
Immediately after I enable the pin interrupt - the interrupt occurs.
It happens every time I try it, no matter what the polarity is or
any other parameters I configured (I think I tried them all).
The inputs are connected to buttons that show a consistent value of
logic '0' (about 0.8v), when not pushed.

Does anybody have an idea of what might be the problem?

Thank you in advance,

Ari



Hi Ari,

In the Motorola SDK on-line documentation, I did a search for "GPIO interrupt",
and I found the following information. You can start the on-line documentation
as follows:
Start
Programs
Motorola
Embedded SDK 2.5
Help and Documentation

In "Contents", go to:
Motorola Embedded SDK
DSP56800/800E Processors
Manuals
DSP56F826/827 User's Manual
8 General Purpose I/O
8.3 GPIO Interrupts

This explains (in quite a bit of detail) just how the GPIO interrupt system
works. You should refer to the User's Manual for the specific processor you are
using, if it is not the DSP56F826/827.

Also, as a general rule for any type of interrupt problem like this, I usually
do one of the following things:

1) Immediately before enabling the interrupt, perform the procedure that is used
to clear the interrupt source. This usually involves reading from or writing to
some of the peripheral registers, and is explained in the User's Manual in the
section that describes that type of I/O (Section 8 in the above example for the
DSP56F826/827 User's Manual General Purpose I/O).

2) Use a flag or a counter, to ignore the first interrupt from the device.

I hope this information helps to solve your problem.

Regards,

Art Johnson
Senior Systems Analyst
PMC Prime Mover Controls Inc.
3600 Gilmore Way
Burnaby, B.C., Canada
V5G 4R8
Phone: 604 433-4644
FAX: 604 433-5570
Email:
http://www.pmc-controls.com

-----Original Message-----
From: atid2 [mailto:]
Sent: Tuesday, November 19, 2002 6:50 AM
To:
Subject: [motoroladsp] GPIO interrupts in DSP56F827 Hi,

I am trying to use the GPIO interrupt mechanism but I have a problem:
Immediately after I enable the pin interrupt - the interrupt occurs.
It happens every time I try it, no matter what the polarity is or
any other parameters I configured (I think I tried them all).
The inputs are connected to buttons that show a consistent value of
logic '0' (about 0.8v), when not pushed.

Does anybody have an idea of what might be the problem?

Thank you in advance,

Ari
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Hi all,

After a few weeks of breaking everything around me, I found the
problem with the GPIO interrupts:
I'm using port C on the DSP56F827 and it's pins are multiplexed.
Apparently the SRD(GPIO C0) and SRFS(GPIO C1) pins were connected to
a stereo CODEC in the EVM , which triggered the interrupts (although
the pins were configured to be controlled by GPIO and not the
peripherals).
Only after I physically disconnected R49 and R50, the interrupt
stoped from reoccurring.
It amazes me how motorola can sell a product with such a problem -
but I guess I'm a newbie.

Cheers,
Ari
--- In motoroladsp@y..., "Art Johnson" <art@p...> wrote:
> Hi Ari,
>
> In the Motorola SDK on-line documentation, I did a search
for "GPIO interrupt", and I found the following information. You
can start the on-line documentation as follows:
> Start
> Programs
> Motorola
> Embedded SDK 2.5
> Help and Documentation
>
> In "Contents", go to:
> Motorola Embedded SDK
> DSP56800/800E Processors
> Manuals
> DSP56F826/827 User's Manual
> 8 General Purpose I/O
> 8.3 GPIO Interrupts
>
> This explains (in quite a bit of detail) just how the GPIO
interrupt system works. You should refer to the User's Manual for
the specific processor you are using, if it is not the DSP56F826/827.
>
> Also, as a general rule for any type of interrupt problem like
this, I usually do one of the following things:
>
> 1) Immediately before enabling the interrupt, perform the
procedure that is used to clear the interrupt source. This usually
involves reading from or writing to some of the peripheral
registers, and is explained in the User's Manual in the section that
describes that type of I/O (Section 8 in the above example for the
DSP56F826/827 User's Manual General Purpose I/O).
>
> 2) Use a flag or a counter, to ignore the first interrupt from the
device.
>
> I hope this information helps to solve your problem.
>
> Regards,
>
> Art Johnson
> Senior Systems Analyst
> PMC Prime Mover Controls Inc.
> 3600 Gilmore Way
> Burnaby, B.C., Canada
> V5G 4R8
> Phone: 604 433-4644
> FAX: 604 433-5570
> Email: art@p...
> http://www.pmc-controls.com >
>
> -----Original Message-----
> From: atid2 [mailto:ari@a...]
> Sent: Tuesday, November 19, 2002 6:50 AM
> To: motoroladsp@y...
> Subject: [motoroladsp] GPIO interrupts in DSP56F827 > Hi,
>
> I am trying to use the GPIO interrupt mechanism but I have a
problem:
> Immediately after I enable the pin interrupt - the interrupt
occurs.
> It happens every time I try it, no matter what the polarity is or
> any other parameters I configured (I think I tried them all).
> The inputs are connected to buttons that show a consistent value
of
> logic '0' (about 0.8v), when not pushed.
>
> Does anybody have an idea of what might be the problem?
>
> Thank you in advance,
>
> Ari >
> _____________________________________
> Note: If you do a simple "reply" with your email client, only the
author of this message will receive your answer. You need to do
a "reply all" if you want your answer to be distributed to the
entire group.
>
> _____________________________________
> About this discussion group:
>
> To Join: motoroladsp-subscribe@y...
>
> To Post: motoroladsp@y...
>
> To Leave: motoroladsp-unsubscribe@y...
>
> Archives: http://www.yahoogroups.com/group/motoroladsp
>
> More Groups: http://www.dsprelated.com/groups.php3 > ">http://docs.yahoo.com/info/terms/