I have to provide extra delay after DRDY LOW goes low-ADS1262

hello chris,

in my code after issuing START conversion command  i simply wait for DRDY to go low.

do nothing when it goes low then issue command to read data . there i am facing this issue. if i remove delay it reads zero.

i checked SPI communication over SPI it seems ok to me.

//  in pulse conversion mode

while(1)
{
cs_low;
_delay_cycles(100);
transfer_bytes(START1);

wait for conversion to complete();     // this is an while(DRDY_HIGH)loop which wait till DRDY goes low.

delay(250);    //genrate 250 ms delay       i am talking about this delay


x[]= read_adc_data();


switch_input_at_adc_channel();

transfer_byte(STOP1);                     // stop start command to start bpulse conversion again

}

now in above code if i remove delay(250)  when i run first time drdy goes low but read zero  but it does not go HIGH again when loop runs second time. means issuing STOP START SEQUENCE doesn't start the conversion 2nd time (checked on oscilloscope).

if i use delay it runs ok

behaviour is different for continious conversion mode

Hi Sasuke,

Likely, things will work better if you move the delay before the While loop.

Waiting for /DRDY with a while loop can be very error prone, as you have very little control over the loop timing, especially if other processes are running on your microcontroller...If you can, try to utilize a fall-edge triggered interrupt.

Best Regards,
Chris

hi chris,

                     ithink i had did the same as you are suggesting. in wait for DRDY there is flag which is set in falling edge triggered ISR of DRDY [i have taken drdy as external interrupt].

while(!DRDY_FLAG);

external interrupt ISR()
{DRDY_FLAG=1;}

IS there any chance of this happening because i cant find any reason. is this hardware problem or something with my code