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  1. #1
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    UART Communication between GSM and GPS

    I want to establish a UART Communication between GSM and GPS.
    The Supply Voltage of GPS is 3.3V.
    The Supply Voltage of GSM is 3.8V.

    The measured RX/TX Voltage Levels of GPS is 2.8V and 0V (for logic High and logic Low).
    The measured RX/TX Voltage Levels of GSM is 1.8V and 0V (for logic High and logic Low).

    Since there is a difference between RX/TX logic levels of the GSM and GPS, So I am
    not able to establish the UART Communication between GSM and GPS.

    I am using the inbuilt interpreter of the Telit GSM module to process the inputs of the GPS.
    I am not using any micro-controller in between GSM and GPS

    Please suggest me a possible way to perform voltage (or Logic) level shifting.

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  2. #2
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    Re: UART Communication between GSM and GPS

    Hi,

    First read both datasheets.
    especially:
    V_IL, V_IH, V_OL, V_OH and the allowed (operational) input voltage range.

    Then do a forum search for "logic level shift", "logic level converter" and simiala search.
    This topic has been discussed many times.

    Also have a look at the box "similar threads" below.

    ***
    Note: This is not a problem related to GSM or GPS, but it is a general problem with connecting ICs with different supply voltages.
    Thus I don´t recommend to do a search with "GSM", "GPS" or "UART", because this just limits the hits.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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