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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 donīt recommend to do a search with "GSM", "GPS" or "UART", because this just limits the hits.

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



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