UART Communication between GSM and GPS

Submitted by Ankur on Mon, 04/22/2019 - 21:03

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.

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

What GSM or GPS module are you using?

I do not understand the part where you say the GSM and GPS should communicate with each other. Normaly a microonctroller is used to communicate with these two modules. 

  Joined August 16, 2016      997
Tuesday at 12:29 AM

I am using the interpreter of the telit gsm to process the data recieved from the GPS

  Joined April 22, 2019      1
Monday at 09:00 PM

Did you check for baud rate? Your GSM modem and GPS should work in same baudrate for them to talk to each other.

Provide part number for both, this will help people understand what hardware u r using 

  Joined August 14, 2018      44
Tuesday at 03:25 PM per my knowldge GSM modules usually has output with 1.8V (for example VAUX/PWRMON on Telit LE910), ypu could use it to power level shifter ic.Not sure about GPS module though. Specific part number would be helpful


  Joined April 30, 2019      1
Tuesday at 11:13 PM

To setup a communication between two communication modules or a module with a controlling device, you need to check the baud rate requirement of the modules, from their datasheets, as most of the modules have communication at 9600 baud rate. And for logic level shifter, you can use any logic level shifter to maintain a specific voltage/logic level for both the modules. Here I would like to suggest you SSLA, for getting assistance in your project. Many times, I got assistance from them in my projects.

  Joined April 09, 2020      55
Thursday at 02:40 PM

Check the logic levels of both devices, if they are working on different logic levels, then use a logic level converter.also check if they are sharing same baud rate for UART communication or not.

  Joined August 22, 2019      125
Thursday at 12:29 PM