ADC -> DMA -> Memory

	lhsieh posted on 15 Feb 2010 3:41 PM PST Member 3 Forum Posts

Hi,

I use PSOC3 to do ADC->DMA ->Memory to sample my analog input data then post- processing my ADC data.
ADC( 300K sps, 10 bits) Memory (xdata, ADC_data[300]).

I try to modify some c codes from DMA example projects, but I did not get right sample data from ADC.

Here is my c code:

ADC_DelSig_1_start();
ADC_DelSig_1_start_convert();
Isr_start();
MyChannel=DMA_DmaInitialize(2,1,0,0);
Td=CyDmaTdAllocate();
CyDmaTdSetConfiguration(Td,2,Td,TD_INC_DST_ADR|TD_TERMOUT0_EN);
CyDmaTdSetAddress(td,ADC_DelSig_1_OUTSAMP, (uint16)&ADC_data[0] );
CyDmaChEnable(MyChannel,Td);
CyDmaChSetRequest( MyChannel,1);

Anyone knows how to do it?

Thanks,
Will

Re: ADC -> DMA -> Memory

	anmd posted on 04 Mar 2010 03:35 AM PST Cypress Employee 15 Forum Posts

Here are some modifications that should be done to make this work .

1) TD_SWAP_EN : Since the buffer - ADC_data(Big Endian) and ADC registers(Little Endian) have different endian-ess , you need to enable swap to store data in the proper format

2)ADC Coherency : By default the ADC coherency key is set to low. But in this case(When you read multi bytes from ADC register using single Td) , the last byte read will be mid byte. Hence you need to set the ADC coherency to mid byte .
"ADC_DelSig_1_DEC_COHER=ADC_DelSig_1_DEC_SAMP_KEY_MID;"

3)"ADC_DelSig_1_OUTSAMP" is not an address but it is the value of ADC_DelSig_1_DEC__OUTSAMP register.
There are many such typos in the function used above - the compiler will give you error for other typos and you can correct it yourself.

Regards,
Anu

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ADC -> DMA -> Memory

Re: ADC -> DMA -> Memory