• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 236 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS1115: Returns -1 when using with ESP32 and PCA9306 level converter

Hikmet Tekin
Prodigy 20 points
Part Number: ADS1115
Other Parts Discussed in Thread: PCA9306

Hi everybody, 

I am using ADS1115 adc with ESP32-wroom-32E and PCA9306 level shifter. 

ADC reads value very well but sometimes it returns -1, what can cause this problem. 

Pull-up resistor or etc?

Thanks

  • 0
    TI__Expert 7010 points

    Hi Hikmet,

    Could you provide more detail on your setup and what you mean by "sometimes it returns -1"?

    Do you mean that you are sometimes reading the output code for -1 in two's complement (FFFFh) when you are expecting something completely different?

    If you are expecting an output reading of 0, you may get an output value that is slightly higher, or in this case slightly lower due to the effects the effects of noise, INL, offset, and gain errors.

    Are you using a differential or single-ended input signal?

    Single-ended signal measurements, where VAINN = 0 V and VAINP = 0 V to +FS, only use the positive code range from 0000h to 7FFFh. However, because of device offset, the ADS1115 can still output negative codes in case VAINP is close to 0 V.

    I would also suggest using a logic analyzer or an oscilloscope to make sure the digital communications are working properly. 

    Best Regards,

    Angel