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TMP102: Want to use the ALERT pin to glow a led as well as send interrupt to GPIO08 of ESP8266 pin

AMARENDRA NATH PRAMANIK
Prodigy 20 points
Part Number: TMP102
Other Parts Discussed in Thread: TMP113EVM

Tool/software:

Hi,

I request you to verify the below mentioned schematic that I included into my design. Jumper JP1 included to if I want to attach the ALERT with GPIO to activate the interrupt processing via MCU. And everything else in the design is self-explanatory. One more point I want to clarify, the GPIO08 is not pulled up/ down whereas ALERT pin is pulled up as suggested in the datasheet.

Let me know about any flows, otherwise I will go by this design only.

Thanks & Regards,

Amarendra

  • 0
    TI__Expert 3505 points

    Hi Amerandra,

    The Alert pin does require a pull-up resistor. We normally recommend something between 5-10kohm, but regardless what resistance level you use, the IOL for the Alert pin should be < 3mA. I only see the 330ohm resistor on Alert which is too low, so I'd suggest to increase the resistance.

    In our evaluation modules, we usually include an Alert LED. Here is an example from the TMP113EVM schematic, including the 10k pull-up, inverter and LED. Something like this might be better to ensure you have enough current going through the LED to light it up properly, but don't have too much current into the TMP102 Alert pin. 

    Best,

    Sakeenah 

  • 0 in reply to Sakeenah Khan
    Prodigy 20 points

    Hi,

    Thank you for your expert opinion.

    The design has been originally influenced from MP102EVM Evaluation Board & I calculate around ~3.9 mA current is flowing through the ALERT pin.

    I will try to implement your feedback but in that case one more additional component is required the SN74AUP1G0....

    It will be very helpful if you also indicate how do I send interrupt to GPIO08 pin of ESP8266 module. Should I directly connect the ALERT pin with the GPIO08?

    Please let me know.

    With Best Regards,

    Amarendra 

  • 0 in reply to AMARENDRA NATH PRAMANIK
    TI__Expert 3505 points

    Hi Amarendra, 

    This circuit also works, I would just suggest to increase the Alert's pull-up value to ensure IOL is not greater than 3mA. 

    I can't give specific advice on ESP8266, but yes you should be able to just connect the TMP102 alert pin to one of the ESP8266's GPIO pins.

    Best regards,

    Sakeenah