G.FIT User Guide and Specification, Rev 2.0_Alpha.14
Page 31 of 117
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5.2.2
Custom data characteristic
The custom data characteristic can be used to send the user weight and/or bicycle weight that is currently in
use by G.FIT to a BLE display, as well as to send manufacturer specific data fro m the fitness equipment to
the display.
Table 5-8. Custom data characteristic structure
Op code
Parameter
Octet order
N/A
Little-endian
Data type
uint8_t
uint_8_t[5]
Table 5-9. Op code and parameters
Op code
Definition
Parameter
0x00
Reserved for future use.
N/A
0x01
Configured user weight.
Current user weight (uint32_t in
0.005kg)
0x02
Configured bicycle weight.
Current bicycle weight (uint16_t in
0.05kg)
0x03-0xDF
Reserved for future use.
N/A
0xE0-0xFF
Manufacturer specific op codes
Defined by manufacturer.
5.2.3
Procedures
5.2.4
Setting the user and/or bicycle weight
The figure below shows the message flow that occurs when a BLE display is used to set the user weight on a
G.FIT module. To set the bicycle weight, follow the same process, but include op code 0x02 for bicycle
weight instead of 0x01 for user weight.