DIYmalls G28U7FTTL GPS Receiver Module User Manual

1. Introduction

The DIYmalls G28U7FTTL is a compact GPS receiver module designed for various applications, including Arduino projects, FPV drones, and flight control systems. This module features a built-in LNA signal amplifier and flash memory for saving configurations. It provides accurate positioning data via NMEA-0183 protocol at a baud rate of 9600bps and an update rate of 1Hz. The module operates within a voltage range of 3.3V to 5V and includes a high-sensitivity ceramic antenna.

Figure 1: DIYmalls G28U7FTTL GPS Receiver Module.

2. Product Features

• Compact size: 28x28x8.5mm.
• Integrated LNA signal amplifier for enhanced reception.
• Onboard flash memory for configuration storage.
• Red LED indicates power supply status.
• Green LED indicates GPS fix status.
• 25x25x4mm high-sensitivity ceramic antenna.
• Compatible with Arduino, FPV drones, flight controllers, and Windows systems.
• Includes 3 cables for easy connection to breadboards, USB to TTL modules, or PCs.

3. Package Contents

• 1x G28U7FTTL GPS Receiver Module
• 3x Connection Cables

4. Specifications

Figure 2: G28U7FTTL module with dimensions (28mm x 28mm x 8.5mm).

5. Setup Guide

5.1 Pinout Diagram

Understand the pin assignments for proper connection:

Figure 3: Pinout diagram for the G28U7FTTL module. EN: Power enable (high level or floating for ON, low for OFF), GND: Ground, RXD: TTL Interface data input, TXD: TTL Interface data output, VDD: System main power supply 3.3V-5V (working current 25mA), PPS: Time standard pulse output.

5.2 Connecting to Arduino

To connect the G28U7FTTL module to an Arduino board, follow these connections:

• VDD (GPS) to 5V (Arduino)
• GND (GPS) to GND (Arduino)
• TXD (GPS) to Digital Pin 4 (Arduino)
• RXD (GPS) to Digital Pin 3 (Arduino)

Figure 4: G28U7FTTL module wired to an Arduino board.

5.3 Connecting to PC via USB to TTL Module

For PC communication and configuration, use a USB to TTL module. Connect as follows:

• VDD (GPS) to 5V (USB to TTL)
• GND (GPS) to GND (USB to TTL)
• TXD (GPS) to RXD (USB to TTL)
• RXD (GPS) to TXD (USB to TTL)

Figure 5: G28U7FTTL module connected to a USB to TTL adapter.

After connecting, plug the USB to TTL module into your computer. A driver may be required for Windows to recognize the USB to TTL module.

Figure 6: G28U7FTTL module connected to a laptop, ready for software configuration.

6. Operating Instructions

6.1 LED Indicators

• Red LED: Indicates power supply. It should be steadily lit when the module is powered.
• Green LED (PPS): Indicates GPS fix status. It will flash once a satellite fix is acquired.

6.2 U-center Software Configuration

The G28U7FTTL module can be configured using u-blox's U-center software. This software allows you to change parameters such as baud rate, update rate, and enabled GNSS constellations.

1. Install U-blox Driver and U-center Software: Download and install the necessary drivers and U-center software from the official u-blox website. Ensure you select the correct drivers for your operating system.

Figure 7: U-center software download page. Download the appropriate version for M9 products and below.
2. Install CP210X Driver: If using a USB to TTL converter, install the CP210X driver on your computer.


Figure 8: U-center driver installation, ensure Windows USB Serial Driver is selected.

3. Connect Module: Connect the G28U7FTTL module to your PC using the USB to TTL adapter as described in Section 5.3.
4. Open U-center: Launch U-center, select the correct COM port for your USB to TTL adapter, and set the baud rate to 9600.


Figure 9: U-center displaying NMEA data from the GPS module.

5. Configure Baud Rate:
   • Open the menu bar View -> Configuration View -> PRT (Ports).
   • Enter the desired baud rate (e.g., 115200) and click Send.
   • After changing the baud rate, you must switch to the new baud rate in U-center to continue receiving data.
6. Configure Update Rate:
   • Open the menu bar View -> Configuration View -> RATE (Rates).
   • Enter the desired measurement period (e.g., 100 ms for 10Hz update rate) and click Send.
7. Save Configuration: To save your changes permanently to the module's flash memory:
   • Open the menu bar View -> Configuration View -> CFG (Configuration).
   • Select Save current configuration and choose FLASH under Devices.
   • Click Send to save the modifications.

6.3 Video Tutorial: GPS Receiver Configuration in U-center

7. Maintenance

• Keep the module clean and free from dust and moisture.
• Avoid exposing the module to extreme temperatures or direct sunlight for prolonged periods.
• Handle with care to prevent physical damage to the ceramic antenna or PCB.
• Ensure proper ventilation if enclosed in a casing to prevent overheating.

8. Troubleshooting

• No Power (Red LED Off):
  • Check power connections (VDD and GND) to ensure they are correctly wired and receiving 3.3V-5V.
  • Verify the power source is active.
• No GPS Fix (Green PPS LED Not Flashing):
  • Ensure the module has a clear view of the sky. Indoor use or obstructions can prevent satellite acquisition.
  • Allow sufficient time (several minutes) for the module to acquire a fix, especially during the first use or after a long period of inactivity (cold start).
  • Check antenna orientation; the ceramic antenna should generally face upwards.
  • Verify that the GNSS constellations are enabled in U-center software (refer to Section 6.2).
• No Data Output / Incorrect Data:
  • Confirm RXD and TXD connections are correctly cross-wired (TXD of GPS to RXD of receiver, RXD of GPS to TXD of receiver).
  • Ensure the baud rate set in your software (e.g., Arduino Serial Monitor, U-center) matches the module's baud rate (default is 9600bps).
  • Check for driver installation issues if connecting via USB to TTL.
  • Verify that the NMEA-0183 protocol is enabled in U-center.
• Module Not Recognized by PC:
  • Reinstall the USB to TTL driver (e.g., CP210X).
  • Try a different USB port or cable.
  • Ensure the USB to TTL module itself is functioning correctly.

9. Warranty

This DIYmalls G28U7FTTL GPS Receiver Module comes with a 30-day warranty. For warranty claims or returns, please contact the seller or refer to the purchase platform's return policy.

10. Support

For further assistance, technical support, or additional resources, please visit the official DIYmalls store or website:

• DIYmalls Store: DIYmalls Amazon Store
• General Inquiries: Refer to the product page or contact the seller directly for specific inquiries.