DAC output is turning in the loop

Anonymous · ‎Aug 10, 2018

Hi everyone!

I got some problem about DAC(8 bit)

I got 32 bit ADC input and I'm trying to configurate this input with DAC 8 bit output I made something but i have some problem looks like

while I changing my input my DAC output changing too but not stable I change my input such as 36725 to 36027 my DAC output is

255 to 0 it is ok but if I change my input to down such as from 36027 to 35822 my output turning back to 255 and in continues time to 0

but I want my input was 2^32 output should be 255 my input was 0 output should be 0

How can I do it?

I attached my file

Bob_Marlowe · ‎Aug 10, 2018

The DMA is configured to transfer 1 byte only from the ADC to the VDAC, not a 32 bit value.

Using both DMA and Getresult() API at the same time will not work at all.

You need to call IsEndConversion() API to wait until a conversion is complete.

The expression

A_OUTPUT = ((ADC_DelSig_1_GetResult32() - 1000) * 0.0015625);

will deliver negative values for counts < 1000.

Getting all together:

When the output frequency is low (kHz) you have time enough not to use DMA at all and do a conversion to optimize the output to the VDAC

There are examples for DELSIG that are not using DMA, try one of those

Bob

Re: DAC output is turning in the loop