Welcome Guest,Register Now
Log In



G.FIT is a turnkey dual-protocol ANT/Bluetooth® low energy technology (BLE) solution for wireless fitness equipment and smart bike trainers, optimized for group and classroom training applications (e.g., leader board applications) with 50+ fitness devices and multiple receivers.  G.FIT is exclusively available on modules from Garmin Canada Inc.

G.FIT Meets the challenges of group fitness

Garmin Canada Inc. has evolved individual fitness machines and smart bike trainers to incorporate wireless standards group fitness capabilities. The G.FIT solution is the result of that evolution, and solves the challenges of group fitness:

  • G.FIT works around WiFi interference to ensure large groups of 50+ devices can connect concurrently.
  • G.FIT solves pairing and setup difficulties with dual protocol support for both ANT+ and BLE heart rate monitors.
  • G.FIT makes it easy for non-technical users to pair by using proximity pairing and list pairing features.
  • G.FIT solves personal device pairing by re-broadcasting ANT+ or BLE heart rate data and works with Bluetooth FTMS (including Control Point) and the ANT+ FE-C Device Profile so that people can record entire workout sessions on their own personal devices.
  • G.FIT enables technology maintenance with both built-in support for easy wireless updates and the addition of custom tailored features and controls using the G.FIT SDK.


Product Brief (PDF) Datasheet(PDF) G.FIT Downloads

G.FIT Module Features

Garmin Canada Inc. offers G.FIT Fitness Equipment Modules, based on Nordic Semiconductor’s nRF52832 SoC supporting ANT+ and Bluetooth® low energy technology features aimed at fitness equipment applications and gym environments. Please refer to the G.FIT User Guide and Specification for more information about the G.FIT Library, serial interface. G.FIT modules include:

  • Nordic Semiconductor’s nRF52832 chip with 64kB RAM, 512kB Flash and a 32-bit ARM Cortex M4F CPU
  • Concurrent ANT and Bluetooth protocol operation using the S332 SoftDevice (a pre-compiled protocol stack solution for nRF52 SoCs)
  • Preloaded fitness equipment focused G.FIT Network Processor application including:
    • ANT+ FE-C with diversified frequency support and HRM device profile support
    • Bluetooth HRS/HRP (heart rate profile and service), FTMS/FTMP (fitness equipment machine service profile) and DIS (Device Information Service)
    • Enhanced coexistence support for group applications
    • Wireless and serial firmware update support
  • Certification of compliance with radio standards in major markets including North America, Australia / New Zealand, Japan and Korea. Declared conformity with radio regulations and requirements for Europe
  • Qualification by the Bluetooth SIG
  • G.FIT Library and SDK for building custom fitness equipment applications or MCU implementations using the nRF52832 SoC – refer to the G.FIT User Guide and Specification for more information
  • G.FIT modules come with RSSI calibration information stored from the factory
  • G.FIT modules are serialized from the factory with an ANT ID to ensure unique device IDs in G.FIT products
  • D52Q models support hardware drop-in compatibility with Garmin Canada FIT2 modules and other Garmin Canada M4 form factor modules (C7, AP2, N5, D52Q in certain configurations) . For drop-in replacements, the G.FIT serial interface will need to be implemented on the host MCU.
  • D52M models (M8 form factor) provide a new, smaller form factor for fitness equipment modules

Module Hardware

  • Integrated printed antenna
  • On-board 32MHz and 32.768 kHz crystal clocks
  • 1.7V - 3.6V supply (D52QGFM4IA, D52MGFM8IA)
  • 1.71V - 3.6V supply (D52QGFM4IA-A)
  • Operating temperature: Industrial (-40°C to +85°C)
  • Up to 30 GPIOs (D52QGFM4IA)
  • Up to 24 GPIOs (D52QGFM4IA-A, D52MGFM8IA)
  • Programmable output/channel from -20dBm to 4dBm
  • Excellent receiver sensitivity
    • -93dBm (ANT mode)
    • -96dBm (BLE mode)
  • 1dBm resolution RSSI
  • Total 512kB flash, 64kB RAM
  • SPI, I2C and UART interface
  • ARM SWD interface
  • Internal DC/DC converter supported
  • 20 x 20mm module (D52Q models, M4 format)
  • 14 x 9.8 x 2.0mm module (D52M models, M8 format)
  • Onboard 3-axis MEMS accelerometer (D52QGFM4IA-A)
    • LIS2DH by ST Microelectronics
    • 2 programmable interrupt pins
  • Layout compatible options with N5150M4CD, N550M4CC, N548M4CB, ANTAP281M4IB, ANTC782M4IB (for D52Q models)
  • Layout compatible options with N5150M8CD, N550M8CC, N548M8CB (for D52M models)
  • Radio regulatory approval for major markets
  • BLUETOOTH SIG qualification
  • RoHS compliant
Picture Module Description Ordering/Package Information Part Status*
D52QGFM4IA 20x20mm module with up to 30GPIOs and 8 analog inputs
  • D52QGFM4IA-TRAY: 20pc in 4x5 tray
  • D52QGFM4IA-REEL: 800pc on 13" tape and reel
D52QGFM4IA-A 20x20mm module with up to 24GPIOs and 5 analog inputs; onboard 3-axis MEMS accelerometer
  • D52QGFM4IA-A-TRAY: 20pc in 4x5 tray
  • D52QGFM4IA-A-REEL: 800pc on 13" tape and reel
D52MGFM8IA 14.0x9.8x2.0mm module with up to 24GPIOs and 8 analog inputs
  • D52MGFM8IA-TRAY:  40pc in 8x5 tray
  • D52MGFM8IA-REEL: 1500pc on 13" tape and reel
D52QSKM6IA-A D52Q module mounted on a carrier board for starter kit and development use with all ANT software libraries and applications, including ANT BLAZE™ and G.FIT™
  • D52QSKM6IA-A-TRAY: 10 pc on 150x165mm tray

* ACTIVE: Device, tool, or software recommended for new designs.

Development with the D52 ANT SoC Module Series (including G.FIT) is supported by a starter kit (D52DK2) and an extender kit (D52EXT1), which is designed to work with the starter kit.  Most components in both kits are also available for sale individually from distributors.

D52DK2 - D52 ANT SoC Module Series Starter Kit

The D52 starter kit (D52DK2) contains all the hardware necessary to develop on the G.FIT platform, other advanced ANT libraries (e.g., ANT BLAZE™), ANT or Bluetooth® low energy technology. The downloadable ANT SoC Module Starter Kit User Manual describes using the kit with reference examples and the nRF5 SDK from Nordic Semiconductor. The G.FIT SDK and the G.FIT User Guide and Specification will be available for download from Thisisant.com.

The kit contents are described below:

Module Part Number Quantity Part Description
D52QSKM6IA-A 2 M4 module mounted on carrier board with 20-pin Molex connector, NFC connections available, SWD programming header, additional through-hole connections for I/O pins
ANTBAT2 2 CR2032 battery board with a Molex socket, a reset button, and a five-position dip switch
ANTIO1 2 I/O board with a Molex connector, a Molex socket, 4 LEDs and 4 buttons
ANTUIF1 1 USB interface board with a Molex socket
  1 Segger J-Link Lite Programmer

D52EXT1 - D52 ANT SoC Module Series Extender Kit

The D52 extender kit (D52EXT1) builds on the D52 starter kit to provide extra nodes and more power for IoT developers and platforms, including G.FIT group gym applications ANT BLAZE™.  The introduction of this kit also coincides with the availability of the ANTBAT3 combination I/O and battery board.  Powered by 2 AA batteries, the development board enables longer testing and development and includes buttons and LEDs for testing input and interaction.  A D52 starter kit is recommended for use with the extender kit, as the starter kit includes the tools necessary to program and monitor development nodes.

The contents of the extender kit are described, below:

Module Part Number Quantity Part Description
D52QSKM6IA-A 4 M4 module mounted on carrier board with 20-pin Molex connector, NFC connections available, SWD programming header, additional through-hole connections for I/O pins
ANTBAT3 4 Combined battery and I/O board with a Molex socket, a reset button, I/O buttons, LEDs and dip switches powered by two AA batteries


Please refer to ANT Wireless or Nordic Semiconductor for licensing information about SoftDevices and associated software.


G.FIT Modules take advantage of ANT+ and Bluetooth features and so use the following ANT/Bluetooth SoftDevice (pre-compiled protocol stack binary):

From ANT Wireless
  • S332 – concurrent ANT and Bluetooth
Included in the G.FIT Software Download Package; see below  

G.FIT Software

G.FIT features are pre-loaded on all G.FIT Modules and are accessed with the G.FIT Network Processor application. In addition, G.FIT features are available in an embedded library which can be used to create custom equipment-specific G.FIT applications using G.FIT modules. G.FIT documentation, the G.FIT embedded library, and the G.FIT SDK are available on the software libraries page.

The G.FIT library download includes the S332 SoftDevice. The package, including a pre-compiled G.FIT Network Processor application, is available as an evaluation download. Note that a commercial license is required to deploy custom applications built using the G.FIT embedded library in an end product.

ANT Software Libraries Download Page

D52 ANT SoC Module Series Conditions of use:

The D52 Series of modules (including G.FIT) have been designed to support the ANT and/or Bluetooth low energy Protocols and are certified for use in many geographic regions around the globe. However, a product incorporating the D52 series module may carry the certification IDs of the module only if it complies with the restrictions and terms, including use of Garmin-approved software, provided in the conditions of use available at:


Discuss this product at the ANT Hardware Products Forum.

In addition to the downloadable resources below, the following documents and resources are available from Nordic Semiconductor's nRF52832 product page, or from the Nordic Semiconductor Infocenter.


  1. nRF52832 Product Specification
  2. nRF52 Series Compatibility Matrix
  3. nRF52832 Objective Product Specification
  4. nRF52 Development Kit Documentation


  1. nRF5 SDK

Downloadable Materials

Title Date Modified Version File Size
G.FIT Fitness Equipment Module Datasheet Aug 31, 2017 1.0 4 MB
G.FIT & D52 Premium Module Manufacturing Considerations Jul 18, 2019 1.0 269 KB
G.FIT User Guide and Specification Sep 19, 2017 1.2 2 MB
ANT SoC Module Starter Kit User Manual Aug 03, 2016 1.0 1 MB
D52M Module M8 Altium Library Mar 15, 2017 8 KB
D52M Module M8 STEP Model Mar 15, 2017 96 KB
D52Q Module M4 Altium Library Mar 15, 2017 8 KB
D52Q Module M4 STEP Model Mar 15, 2017 351 KB
ANT Message Protocol and Usage Apr 02, 2014 5.1 4 MB
ANTware II Nov 12, 2013 4.1.00 1 MB
Interfacing with ANT General Purpose Chipsets and Modules Dec 03, 2010 2.1 443 KB
Interpreting RF Radiation Patterns Sep 23, 2014 1.0 1 MB
ANT USB Interface Board Driver - Windows Oct 03, 2012 156 KB
D52 Series DoC May 09, 2018 1.0 120 KB