UART Communication between GSM and GPS

[aankur]

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.

 

[KlausST]

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