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Facing problems in APPL NOTE AN52705 | Cypress Semiconductor

Facing problems in APPL NOTE AN52705

Summary: 10 Replies, Latest post by naru on 03 May 2012 08:46 AM PDT
Verified Answers: 1
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user_201261815's picture
User
43 posts

Recently i started working on PSoC....

in AN52705 (Getting started with DMA) 

1) In POINT TO POINT transfer project i am unable to get the EXACT SINE WAVE as output if i give a sine wave as a input .The output which i got is in the photo  ...please provide the information in getting the exact sine wave...

2)In POINT TO ARRAY TRANSFER Project how to SEE  the stored data????
 

Attachments: 
U2
uday's picture
Cypress Employee
569 posts

 Could you attach your modified project here ?

user_1377889's picture
User
10803 posts

To "see" variables:

Use the debugger's "Watch" facility (right-click on the var when project is halted) or look at the contents of memory.

Bob

hli
user_78878863's picture
User
2759 posts

This signal looks like value overflow to me. Could it be that your ADC is set to differential mode, or to a resolution other than 8 bits? (Look at the datasheet of the DelSigADC, page 11 to see what I mean)

dasg's picture
Cypress Employee
730 posts

Hi naru,

 

It's a clear case of overflow of the ADC Value.

a) Try giving an input signal which is well withing the input voltage range of the ADC.

b) From what I can observe from the waveform, the offset in the input signal is quite high. If you reduce the offset to a lower value such that for the same amplitude, the input signal's peak to peak voltage is within the ADC's input range, the output obtained from VDAC will be a faithful reproduction of the input signal. (Remember that at no point of time should the input signal's amplitude go below the digital ground value)

U2
uday's picture
Cypress Employee
569 posts

Without the project we cant really guess what the problem is. First we do not know if he is using ADC at all to sample the Sine. Could be that hard coded values are simply dumped using the DMA, the author of this post needs to clarify this. Sometimes, the offset error can occur if there is one byte shift in the DMA due to endianess mismatch. I have seen this in the past. 

user_201261815's picture
User
43 posts

1) In POINT TO POINT transfer project i gave the input as  sine wave and i maintained it's  peak to peak voltage within  the ADC's input range....now i got sine wave as output ....but if  i gave input voltage 1.5V  i am getting the output voltage voltage as 0.5V....how to avoid ths????

 

user_201261815's picture
User
43 posts

In POINT TO ARRAY TRANSFER Project  after programming i am unable to see the "watch window" in the debug.....please provide info regarding this.....

in PSOC programmer for the same project i got the output as in pic.....please say what it means???? 

 

user_1377889's picture
User
10803 posts

You've got a miniprog3 and should set it up for SWD interface (Ribbon cable). With that you'll have full debugging capabilities.

You used the Miniprog and the Programmer-software which works, but doesn't give you all the possibilities.

 

Bob

user_201261815's picture
User
43 posts

i kept the miniprog3 in SWD interface now its not showing the "port accquire window" and "watch window" also

please give info how to avoid this......

can i see the sampled output on "LCD"??????

user_201261815's picture
User
43 posts

PLEASE PROVIDE  SOME INFORMATION REGARDING MY DOUBTS............

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