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Question about timers of 56F807

Started by swaroop September 25, 2002
hi
Iam working with the ADCs and DAC of a DSP56F807 EVM.
I want to use two Quadrature timers for the 2 ADCs to retrieve the
samples through the conversion complete callback functions .....n two
auxillary timers for giving the digtal signal to the DAC to two
different channels through two timer ISRs.
then how should i design all these timers such that i can go through
all the process without missing any step...i.e retrieving the signals
from adc, processing it and then giving it back to the dacs....
At how much frequencies i should sample my incoming signals and what
are the priorities i should give to my interrupts.....like callbacks
n timerISRs.........
How should I go ahead actually...
this might be a simple thing for u all knowledgeable guys....
but iam very novice to this field....
please give me a helping hand to me...
thanks in advance...
swaroop



Motorola has 2 excellent Application Notes about the ADCs:
AN1933/D "Synchronizing of On-Chip Analog to Digital Converter on DSP56F80x
DSPs"
AN1947/D "DSP56800 ADC"

You can get them at:
http://e-www.motorola.com/brdata/PDFDB/docs/AN1933.pdf
http://e-www.motorola.com/brdata/PDFDB/docs/AN1947.pdf

Motorola has many links to Application Notes for the DSP56F80x DSP chips, just
go to their website at:
http://e-www.motorola.com/webapp/sps/site/homepage.jsp?nodeIdM0ylgz6wY

Then select the chip you are using (for example, DSP56F805):
- In the Search area (top right) enter DSP56F805 and press Go
- Click on the link to "DSP56F805 Product Summary Page"
- On this page scroll down to "DSP56F805 Documentation"
- You will see a section titled "Application Note", this has links to all the
Application Notes that apply to the DSP56F805 chip I hope this helps.

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: swaroop [mailto:]
Sent: Wednesday, September 25, 2002 6:48 AM
To:
Subject: [motoroladsp] Question about timers of 56F807 hi
Iam working with the ADCs and DAC of a DSP56F807 EVM.
I want to use two Quadrature timers for the 2 ADCs to retrieve the
samples through the conversion complete callback functions .....n two
auxillary timers for giving the digtal signal to the DAC to two
different channels through two timer ISRs.
then how should i design all these timers such that i can go through
all the process without missing any step...i.e retrieving the signals
from adc, processing it and then giving it back to the dacs....
At how much frequencies i should sample my incoming signals and what
are the priorities i should give to my interrupts.....like callbacks
n timerISRs.........
How should I go ahead actually...
this might be a simple thing for u all knowledgeable guys....
but iam very novice to this field....
please give me a helping hand to me...
thanks in advance...
swaroop

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A convienent feature built into the chip is the usage of Quad timers C2 and C3.  If you can setup a PWM unit as your base time, the ADC's can be triggered to start a conversion using timers C2 and C3.  Then, a single interrupt routine can be used to read the conversion results, process the data, and start the DAC update process.  I do not use the EVM SPI based DAC, but use the ADC data in this way.
 
Jerry.
-----Original Message-----
From: swaroop [mailto:s...@yahoo.com]
Sent: Wednesday, September 25, 2002 8:48 AM
To: m...@yahoogroups.com
Subject: [motoroladsp] Question about timers of 56F807

hi
Iam working with the ADCs and DAC of a DSP56F807 EVM.
I want to use two Quadrature timers for the 2 ADCs to retrieve the
samples through the conversion complete callback functions .....n two
auxillary timers for giving the digtal signal to the DAC to two
different channels through two timer ISRs.
then how should i design all these timers such that i can go through
all the process without missing any step...i.e retrieving the signals
from adc, processing it and then giving it back to the dacs....
At how much frequencies i should sample my incoming signals and what
are the priorities i should give to my interrupts.....like callbacks
n timerISRs.........
How should I go ahead actually...
this might be a simple thing for u all knowledgeable guys....
but iam very novice to this field....
please give me a helping hand to me...
thanks in advance...
swaroop


_____________________________________
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Yes, there is a very good description about how to implement this feature in Application Note AN1933/D.
 
Art Johnson
 
-----Original Message-----
From: Johnson, Jerry [mailto:j...@giddings.com]
Sent: Wednesday, September 25, 2002 9:04 AM
To: 'swaroop'; m...@yahoogroups.com
Subject: RE: [motoroladsp] Question about timers of 56F807

A convienent feature built into the chip is the usage of Quad timers C2 and C3.  If you can setup a PWM unit as your base time, the ADC's can be triggered to start a conversion using timers C2 and C3.  Then, a single interrupt routine can be used to read the conversion results, process the data, and start the DAC update process.  I do not use the EVM SPI based DAC, but use the ADC data in this way.
 
Jerry.
-----Original Message-----
From: swaroop [mailto:s...@yahoo.com]
Sent: Wednesday, September 25, 2002 8:48 AM
To: m...@yahoogroups.com
Subject: [motoroladsp] Question about timers of 56F807

hi
Iam working with the ADCs and DAC of a DSP56F807 EVM.
I want to use two Quadrature timers for the 2 ADCs to retrieve the
samples through the conversion complete callback functions .....n two
auxillary timers for giving the digtal signal to the DAC to two
different channels through two timer ISRs.
then how should i design all these timers such that i can go through
all the process without missing any step...i.e retrieving the signals
from adc, processing it and then giving it back to the dacs....
At how much frequencies i should sample my incoming signals and what
are the priorities i should give to my interrupts.....like callbacks
n timerISRs.........
How should I go ahead actually...
this might be a simple thing for u all knowledgeable guys....
but iam very novice to this field....
please give me a helping hand to me...
thanks in advance...
swaroop


_____________________________________
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.

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_____________________________________
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.

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About this discussion group:

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