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I am using TMS320C6713 DSP in my project. 
1) I want to write single fix byte periodically to EMIF CE3 by using timer
interrupt.
2) I want to read single fix byte from EMIF CE3 at external gpio interrupt.

     Read and write strobe widths are 600nsec. i think processor stalls at read
and write. In order to make procedure more efficient i tried to use EDMA because
EDMA can read and write from external address without interrupting the
processor.

It was obseved that the our system became even slower by using the EDMA?

Can anybody explain this to me. 
Can anybody suggest alternative solution to using edma so that we can perform
read and write without interrupting the CPU

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avais,

The Timer periodic interrupt event is going to interrupt the CPU, so I see no
way to 
avoid that.
However, since it is only one byte, the timer interrupt handler function could
be 
nothing more than a simple assignment (read and write) to the I/O address.

The GPIO interrupt event is going to interrupt the CPU, so I see no way to avoid
that.
However, since it is only one byte, the interrupt handler function could be
nothing 
more than a simple assignment (read and save) from the I/O address.

The EDMA is for moving lots of data without interrupting the CPU, except for the
CPU 
starting the I/O sequence and an interrupt event to signal the I/O sequence is 
completed.  Your only moving one byte of data and EDMA cannot be setup to
operate 
periodically so EDMA will not do the job for you. 

Almost always, reads and writes through the EMIF interface involve some number
of wait 
states to wait for the completion of the read or write operation.

The EMIF interface should be setup only once during program initialization.

EDMA requires starting, which takes some CPU time.  That is going to slow down
the 
operation when the I/O is periodic, so it is just wasting CPU cycles to use it
for your 
application.  EDMA is for moving lots of data without the CPU having to do more
than 
start the operation and handle the interrupt that occurs when the operation is 
complete.

For your application, a couple of simple interrupt event handlers will be much
faster 
than EDMA.

If your still having problems, a couple code snips of the interrupt event
handlers 
would help us to suggest fixes.

R. Williams
---------- Original Message -----------
From: a...@gmail.com
To: c...@yahoogroups.com
Sent: Wed, 01 Sep 2010 23:47:24 -0400
Subject: [c6x] TMS320C6713 EDMA Problem

> I am using TMS320C6713 DSP in my project. 
> 1) I want to write single fix byte periodically to EMIF CE3 by using 
> timer interrupt. 2) I want to read single fix byte from EMIF CE3 at 
> external gpio interrupt.
> 
>      Read and write strobe widths are 600nsec. i think processor 
> stalls at read and write. In order to make procedure more efficient i 
> tried to use EDMA because EDMA can read and write from external 
> address without interrupting the processor.
> 
> It was obseved that the our system became even slower by using the EDMA?
> 
> Can anybody explain this to me. 
> Can anybody suggest alternative solution to using edma so that we can 
> perform read and write without interrupting the CPU
------- End of Original Message -------

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