User's Manual

CONFIDENTIAL

2.2. UART Specification

Baudrate: 9600 (default), 4800, 2400, 115200

Parity: No parity

Flow Control: Disable

2.3. Equipment Assumption

Upon power up of the equipment device, the HRM3300 is also power up. Since the equipment is controlling

the HRM3300, the HRM3300 will be on the idle state or waiting state for the command from the equipment

console.

2.4. Equipment and HRM3300 Operation

The equipment console will send “workout” command to HRM3300 to wake up the HRM3300 from idle

state to scanning state. The HRM3300 will start scanning for 5kHz, BLE and ANT+ sensors advertising

within its proximity. The proximity setting is added in the “workout” command send by the console.

The sensors that are found during scanning state will be sent to the Equipment console. For BLE, the

advertising name and BLE address are sent to the console. A separator key is added in between the

advertising name and the BLE address. See the UART package table for the details of communication

protocol. All BLE sensors send to the console are uniquely. This means there are no duplicate for BLE

sensors received by the equipment console.

For ANT+ the advertising ID is sent to the equipment console. There is a possibility of duplication of ANT+

sensors because of the limitation of ANT+ protocol.

For 5kHz, a "5kHz HRM" name is sent. Only one 5kHz sensor is send to equipment console while a

maximum five devices each for BLE and ANT+. Up to maximum of eleven sensors can be sent to the

equipment console. Although the console can receive more than eleven devices, the limitation is due to the

capacity of HRM3300 microcontroller. Maximum capacity might change in the future or upon customer

request.

After all sensors within the pairing proximity range are sent to the equipment console, the user is expected

to choose what type of sensor to be used during workout. If the user selects the BLE device, the

corresponding BLE address is sent back to HRM3300. The BLE address is one of the parameters for pairing

and tracking BLE sensor.

If user selects ANT+ device, the HRM3300 will use the ANT+ advertising name for pairing and tracking. If

there are more than one ANT+ device with the same advertising name then there might be a chance for

the user to pair to a wrong sensor. For 5kHz device, the strongest signal is expected to be paired.

After the HRM3300 successfully paired with the selected sensor, it starts streaming the heart rate data. The

heart rate data will be sent to console. The frequency of heart rate streaming will be dependent upon the

kind of sensor device but for 5kHz it would depend upon the heart rate value.

The equipment console would need to send a “stop workout” command to disconnect the HRM3300 to the

paired sensor. The HRM3300 will forget that sensor device and go to idle state and wait for next

interaction.

A special process was made if only 5kHz was detected during scanning. By default, the HRM3300 will not

wait for user confirmation but directly connect to 5kHz sensor if it is the only one detected during scanning.

HRM data will automatically send to console after connection However console has an option to override it

with “5KHZ disable auto connect” command, in this case the console will wait for user confirmation. A stop

workout command will disconnect the HRM3300 to 5kHz sensor and go to idle state.