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Need help to understand time/frequency graph...ADC with F28335

Mr Jb
Prodigy 50 points

Hello, im using eZdsp - F28335 for ADC conversion.

I have some question regarding the time/frequency graph.

I want to check if my ADC is functioning properly...since my input is a 2.5VDC = 3402bit

I was expecting a straight line in the graph... Instead there are some empty spaces left out in

the graph. I tried changing the TBPRD (frequency) and CMPA.half.CMPA (Duty cycle)..still..the empty spaces are there.

This was done with Acquisition Buffer Size : 200 , Index Increment : 1 and Display Data Size : 200 .

Later in the help file..i found out that acquisition buffer size actually shows the amount of sample..

which i later change it to 90. This time it looks promising..because there are no empty spaces..

straigh line ..however in some duration the empty spaces appears randomly ..dissapears..and back to straight line..etc

I have included the pics in this post..

My question is...

1) The random empty spaces...is this normal ? How can i comfirm that my ADC is working ? There are
previous post that suggest toggling the GPIO and observe using oscilloscope..but i dont have
one.

2) Setting my time display in microsec...in the graph it came out as 2.1e+8 ... 2.5e+8 ... 2.9e+8 ... in the X-axis,
can anyone explain how to read those values ? I've set my epwm with 2khz...

Thanks alot !!