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6.5 Wireless link limitations
Data throughput
The system throughput of the Bluetooth and Wi-Fi links is dominated by the effective I2C and
Bluetooth SPP or Wi-Fi data rates, respectively. It is recommended to limit the average byte load from
ZED-F9P to 17 kB/sec. The following examples approximate the output load of the default
configuration of the ZED-F9P firmware:
•
1 Hz navigation rate: NMEA, UBX-NAV-RELPOSNED, UBX-NAV-PVT enabled < 2.4 kB/sec
•
5 Hz navigation rate: NMEA, UBX-NAV-RELPOSNED, UBX-RXM-RTCM enabled < 17 kB/sec
•
10 Hz navigation rate: NMEA, UBX-RXM-RTCM enabled < 14 kB/sec
ODIN-W2 outputs an error message when the I2C bus load is too high. In such situations, some
messages may get dropped. To avoid this, it is recommended to adjust the enabled messages in the
ZED-F9P I2C interface.
Link loss
6.5.2.1
Bluetooth Classic
During a Bluetooth transmission failure (red LED blinking), check the system for typical root causes:
•
Bluetooth SPP COM port on the host device stalled or disconnected.
•
Insufficient signal quality between the host device and C099-F9P.
Recover the system by restarting ODIN-W2. To do this, press the reset button.
If ZED-F9P is configured through a Bluetooth link, e.g. using UBX-CFG messages, it is recommended
to apply all configurations manually in u-center. Uploading a large configuration file may fail due to the
limited link bandwidth.
6.5.2.2
Wi-Fi 2.4 GHz
A Wi-Fi disconnection is reported by a CLI message from the ODIN-W2 UART1 interface and the LED
indication (yellow LED). If the disconnection is not intended, check the Wi-Fi interface on the host PC.
Wi-Fi channel congestion can be avoided by changing the Wi-Fi AP channel on C099-F9P. Typically,
channel congestion is experienced when the Wi-Fi connection indicators (e.g. LEDs) are OK but no
data is received. Use the following commands to set and read the current channel stored in the
ODIN-W2 RAM:
1.
/wifi_setch/run <integer number 1-11>
2.
/wifi_getch/run
Then, continue with the Wi-Fi connectivity settings, refer to section 6.3 Wi-Fi connectivity. Ensure
C099-F9P is restarted to apply the new channel.
Windows OS issues with Bluetooth SPP
There are some known issues with the Windows Bluetooth serial port profile (SPP) implementation
for Windows 7-10. The symptoms include the Bluetooth Virtual COM port not installing or
Figure 25: ASUS USB-BT400
UBX-18063024 - R16
C1-Public
applications not connecting to the Bluetooth virtual COM port. In other
cases, Windows might crash or become unresponsive. This is not related
to the ODIN-W2 Bluetooth implementation that uses the Bluetooth
standard SPP.
A known industry fix is to not use the Windows Bluetooth stack and PC
Bluetooth hardware. This is done by using a USB Bluetooth adapter that
Wireless communication
C099-F9P - User guide
Page 26 of 43
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