ADS1298: DRDY pin not going low although the other functions working well

Khoi Nguyen

Part Number: ADS1298

Tool/software:

im using a stm32f4 to comm with ads1298. My SPI is okay, i can write and read from that register like CONFIG1, 2, 3 and ID. All works well instead of that DRDY pin, after i using START opcode, it doesnt toggle as expected.
ADS1298_CS_H;
delay_us(10);
ADS1298_PWDN_L;
HAL_Delay(100);
ADS1298_PWDN_H;
HAL_Delay(100);
ADS1298_CS_H;

ADS1298_CMD(ADS1298_RESET);
HAL_Delay(1000);
ADS1298_CMD(ADS1298_SDATAC);
HAL_Delay(10);
    // Set Configuration Register
    ADS1298_REG(ADS1298_WREG|ADS1298_CONFIG1,    0x22);//500SPS

    ADS1298_REG(ADS1298_WREG|ADS1298_CONFIG2,    0x30);
    ADS1298_REG(ADS1298_WREG|ADS1298_CONFIG3,    0xD5);

    ADS1298_REG(ADS1298_WREG|ADS1298_CONFIG4,    0x08);

    ADS1298_REG(ADS1298_WREG|ADS1298_CH1SET,     0x05);
    //ADS1298_REG(ADS1298_WREG|ADS1298_CH1SET,     0x05);//
    ADS1298_REG(ADS1298_WREG|ADS1298_CH2SET,     0x05);
    HAL_Delay(10);

    //start conversion

    ADS1298_START_L; //confirm that start pin is tie to LOW level
    delay_us(100);
    ADS1298_START_H;
ADS1298_CMD(ADS1298_RDATAC);

Here is my code.

6 months ago

0 Ryan Andrews 4 months ago

TI__Guru 66166 points

Hello Khoi,

My apologies for missing your post. Do you still need help with initializing the ADS1298?

Regards,

Ryan

0 Khoi Nguyen 4 months ago in reply to Ryan Andrews

Prodigy 50 points

hi Ryan,
yea i still need help with that chip. My problem still there, the SPI transfer is just okay, but the DRDY pin not toggling when i send the START CMD

0 Ryan Andrews 4 months ago in reply to Khoi Nguyen

TI__Guru 66166 points

Thanks, Khoi. Can you please follow the suggestions in the FAQ page below and let me know the results? I would like to confirm that power supplies are measuring as expected and that the POR initialization sequence is being followed:

[FAQ] ADS129x: How do I verify that my ADS129x device is still functional? - Data converters forum - Data converters - TI E2E support forums

Also, would you mind providing the ADS1298 portion of your schematic so we can review the relevant connections?

Regards,

Ryan

0 Khoi Nguyen 4 months ago in reply to Ryan Andrews

Prodigy 50 points

Hi Ryan, ofc the sequence is like expected. The FAQ above, only the step 5 and 6 is not work for me, my DRDY doesnt toggle at all.
And these things about SPI transfer is just okay.
8662.ads1298.pdf
And here is my schematic!

0 Ryan Andrews 4 months ago in reply to Khoi Nguyen

TI__Guru 66166 points

Hello Khoi,

Are you using internal or external clock mode? Only R65 or R60 should be installed, but not both. If you are using external clock mode (OSC1), install R65 and remove R60. If using internal clock mode, install only R60 and ensure that your MCU is pull the pin high to DVDD level.

Can you check the clock settings?

Regards,

Ryan

0 Khoi Nguyen 4 months ago in reply to Ryan Andrews

Prodigy 50 points

Hi Ryan, i've found how to resolve this issue. My RESET state was driven low so that the chip was not able to toggle the DRDY. Many tks for your help.