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G.FIT User Guide and Specification, Rev 2.0_Alpha.14
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4.1.1
G.FIT CONFIGURATION (OFF)
Each time G.FIT is power cycled, its settings are reset and it enters a special OFF state; during this initial
OFF state, G.FIT is in configuration mode. In this initial OFF state , the application MCU configures G.FIT to
meet the desired behaviour for the given fitness equipment and required use case. All commands that are
used to configure G.FIT must be sent in this state. There are some minimum requirements that G.FIT
requires before transitioning from OFF to READY, see section 4.3 for the minimum G.FIT configuration
sequence.
4.1.2
OFF
This state is used to conserve power and it is recommended that G.FIT be put into this state after sustained
user inactivity.
4.1.2.1
Heart rate receive channels
Both ANT+ and BLE heart rate scan channels are closed.
4.1.2.2
Fitness equipment transmit channels
Both the ANT+ FE-C channel and BLE FTMS peripheral transmit channels are closed.
4.1.2.3
Transitioning from OFF
When transitioning from OFF to READY, the developer should ensure that all channels have finished closing
(see section
4.1.2.1
, and section
4.1.2.2
) before making the transition.
4.1.3
READY
This state should be entered when there is initial user activity or when a user has recently ended a session.
This state opens scanning channels that search for BLE and ANT+ heart rate monitors, allowing the user to
connect their heart rate monitors as they prepare for a workout. Since G.FIT is scanning during this time,
avoid running additional scans on other channels or doing flash writes. It also turns on the ANT+ FE-C
channel and the BLE FTMS peripheral which transmits data describing the user’s workout.
4.1.3.1
Heart rate receive channels
ANT+ and BLE heart rate scan channels are opened and will remain open while in state READY. If a heart
rate monitor is paired to G.FIT, a dedicated channel is opened to establish a connection with that heart rate
monitor, both ANT+ and BLE heart rate scan channels will remain open and scan for heart rates wh en
connected to a heart rate monitor.
4.1.3.2
Fitness equipment transmit channels
The ANT+ FE-C channel is opened and begins transmitting and BLE FTMS peripheral begins advertising. Both
channels will remain open and continue transmitting while in state READY. If a display is paired to G.FIT
while in state IN USE, a connection is established with the display and the BLE FTMS peripheral stops
advertising.
4.1.4
IN USE
This state should be entered when the user has sustained activity or has indicated a desire to start a workout
session by pressing the start button.
4.1.4.1
Heart rate receive channels
The heart rate receive channels have the following behaviour depending on the user interaction .
4.1.4.1.1
No heart rate monitor connected
If G.FIT moves to state IN USE and there are no heart rate monitors connected, then the ANT+ and BLE
heart rate scan channels will remain open for 30 seconds (by default, this can be adjusted using
HR_SetInUseScanTimeout, see section 7.3.4). After 30 seconds the ANT+ and BLE heart rate scan channels