ADS7280

Rodrigo Ladeira

Other Parts Discussed in Thread: ADS7280

Hi...

I have configurate the ADS7280 with the simple code below:

SEL_AD = 1;          //FS/CS
delay_us(1);
START_AD = 1;    // CONVST
delay_us(1);
SCK = 0;
delay_us(30);
SEL_AD = 0;
delay_us(30);
SDO = 1;
delay_us(10);
for(i=0;i<4;i++){
   SCK = 1;
   delay_us(30);
     SCK = 0;
     delay_us(30);
}

SEL_AD = 1;

This configution is for load CFR with default mode, but when I read the CFR I recieve this bites: 0x0DFC. I think that the result is wrong. but I dont know why.....

over 14 years ago

0 Tom Hendrick over 14 years ago

TI__Guru**** 173426 points

Hi Rodrigo,

This looks like you are basically writing correctly to the device (data valid on falling SCLK, FS/CS = 0, CONVST = 1). What happens when you pulse CONVST? Does the BUSY signal go active?

0 Rodrigo Ladeira over 14 years ago in reply to Tom Hendrick

Intellectual 360 points

Hi Tom,

The ADS7280 do not have the Busy pin, but the pin EOC, when I put CONVST = 0 the EOC signal go low and go high after 1us, the duration of the CONVST low pulse, is 30us.

0 Tom Hendrick over 14 years ago in reply to Rodrigo Ladeira

TI__Guru**** 173426 points

Right, EOC/INT - sorry 'bout that... OK - so it sounds like the part is basically working. Using the default register settings, you would be using the internal oscillator for the conversion clock and that would take about 800ns. Can you try writing something other than the default register values and then attempt to read them back? I'd be interested in knowing that you can properly write and read data.

0 Tom Hendrick over 14 years ago in reply to Tom Hendrick

TI__Guru**** 173426 points

Hi Rodrigo,

Did you find the problem here? Were you able to wrtie something other than the defaults and read them back properly?

0 Rodrigo Ladeira over 14 years ago in reply to Tom Hendrick

Intellectual 360 points

Hi Tom,

Sorry for take so long to answer.....The problem was the rise and fall time, because I was using a opto-coupler without a digital output....and this information is not present in the datasheet.

Thanks for your help....

Rodrigo (BRAZIL)

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ADS7280