T114 with Generic GPS module?

Builds / Use Cases
1

Anybody been able to get a generic GPS module to work with the T114?

Seems like the standard RX/TX Pwr and Gnd does not work?

Have several modules on hand and don’t want to be tied to the Heltec GPS.

Any ideas appreciated.

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2

I’ve developed a compatible GPS module that works perfectly fine. It uses Quectel_L76K and has 8 pins, which allows for low power consumption.

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3

image

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4

Thanks. For a novice… do you have an image of the wiring in context ? Cheers.

5

image

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6

All my (20+) nodes use RX, TX GND & PWR only.

Wired to appropriate 4 pins on P3, the GPS is on and producing output data on the TX line.
I am not using the 8 pin, Quectel_L76K module.

Do I need to change anything in the “Position” setup menu?

Do I need to pull any pins on the header up or down for operation?

7

The firmware has already defined the pins, so manual configuration is not required.

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8

Understood, so why is a standard 3 or 4 wire connection not working?

9

The wake_up pin plays a crucial role in determining power consumption, so it’s important. It is recommended to use all 8 pins. The L76K and antenna are very affordable, costing only 4 dollars if you build them yourself.

10

It’s not a cost issue. I already have a quantity of various modules on hand. Including the Quectel_L80 which I use often.

Do you know why the T114 thinks that the GPS is not present?

11

Thx for this important info…!
Best regards, Paul

12

The pinout for Header 8, P3 and the color graphic of the connector P3 do not agree for pins 1,2 3,&4 So which is correct? Does anybody know?

Color graphic P3  (from docs)    P3, Header 8 (from schematic)

* GPIO39/RX_GPS..................*RST_GPS.........Pin 1
* GPIO34/WAKE_UP.................*PPS.............Pin 2
* GPIO36/PPS.....................*WAKE_UP.........Pin 3
* GPIO38/RST_GPS.................*RX_GPS..........Pin 4

See pics above^
13

The published info as it stands is incorrect.

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