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Question regarding interrupts in DSP56F805

Started by Chandrasekar Ramkumar April 19, 2005

Hi Rick,

I read thru the AN2283 document, which explains the interrupt structure in 805. In my program i have used the Transmit buffer 0 to store the message. I initially stored the message in Transmit buffer 0 and clear the TXE0 flag by writing 1 to it. I also set TXEIE0 to give a transmit interrupt. But after this the MSCAN does not set the TXE0 flag to transmit the message. I am not sure if we shld set the flag or wait for the TXE0 flag to be set.
 
Cheers,
Chandru

 



--
Chandru Ramkumar,
828 S Claremont Ave,Apt#1
Chicago-IL 60612
Hi Chandru
 
I don't remember it well enough to just answer.  I would have to re-read the docs and look at my code for a while to give a good answer.  I can only do that after work hours, and I know I have to work until 7:00 today anyway, to catch up on some things.  I'll answer as soon as I can.
 
It may be hard to get a real interrupt to occur - I don't know if you are using something like the old SDK or setting up interrupt registers yourself - don't forget to set a priority (GRP register?  IPR? ITCN?) as well as the right vector.
 
If the chip is really sending the packet out on the wire, it should be easier to see the "TX Empty" flag being sent, than to get a real interrupt to fire.  A scope should tell you if the packet really is being sent.  Probably it will not be sent "successfully" until some other chip (or the loopback) ACKs the packet being sent.  I forget if MSCAN will set "TX Empty" (or whatever the flag really is) if it gets no ACK.
 
I forget if just looking at the CAN registers with the debugger will confuse the MSCAN peripheral - the debugger seems to read the registers in order to display them, and maybe reading one of them will change its state.  (I forget.)
 
Rick Corey
-----Original Message-----
From: m...@yahoogroups.com [mailto:m...@yahoogroups.com]On Behalf Of Chandrasekar Ramkumar
Sent: Tuesday, April 19, 2005 1:12 PM
To: m...@yahoogroups.com
Subject: [motoroladsp] Question regarding interrupts in DSP56F805

Hi Rick,

I read thru the AN2283 document, which explains the interrupt structure in 805. In my program i have used the Transmit buffer 0 to store the message. I initially stored the message in Transmit buffer 0 and clear the TXE0 flag by writing 1 to it. I also set TXEIE0 to give a transmit interrupt. But after this the MSCAN does not set the TXE0 flag to transmit the message. I am not sure if we shld set the flag or wait for the TXE0 flag to be set.
 
Cheers,
Chandru

 



--
Chandru Ramkumar,
828 S Claremont Ave,Apt#1
Chicago-IL 60612NEW!  You can now post a message or access and search the archives of this group on DSPRelated.com:
http://www.dsprelated.com/groups/motoroladsp/1.php

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Hi Chandru
 
I recently had a question for Freescale Tech Support about FlexCAN (on the 56F8357), and they sent me some sample code as well as answering the question.  It was for the '8357, so it won't help you with the '805 (MSCAN).
 
However, if you ask them your question, maybe they have sample code for the '805 they would share!
 
Here is the link:
https://www.Freescale.com/webapp/ruhp.login.framework
 
They will ask you to register by giving your name and so on, but they are very good about answering questions.
 
Rick Corey
-----Original Message-----
From: m...@yahoogroups.com [mailto:m...@yahoogroups.com]On Behalf Of Chandrasekar Ramkumar
Sent: Tuesday, April 19, 2005 1:12 PM
To: m...@yahoogroups.com
Subject: [motoroladsp] Question regarding interrupts in DSP56F805

Hi Rick,

I read thru the AN2283 document, which explains the interrupt structure in 805. In my program i have used the Transmit buffer 0 to store the message. I initially stored the message in Transmit buffer 0 and clear the TXE0 flag by writing 1 to it. I also set TXEIE0 to give a transmit interrupt. But after this the MSCAN does not set the TXE0 flag to transmit the message. I am not sure if we shld set the flag or wait for the TXE0 flag to be set.
 
Cheers,
Chandru

 



--
Chandru Ramkumar,
828 S Claremont Ave,Apt#1
Chicago-IL 60612NEW!  You can now post a message or access and search the archives of this group on DSPRelated.com:
http://www.dsprelated.com/groups/motoroladsp/1.php

_____________________________________
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:

Archives:  http://www.dsprelated.com/groups/motoroladsp/1.php

To Post:  Send an email to m...@yahoogroups.com

Other DSP Related Groups: http://www.dsprelated.com/groups.php