Bluetooth HC-05 serial speed rate vs Bluetooth transmission speed

[neonwarrior]

Hello everyone,

Why is the maximum serial speed rate of HC-05 (460800 baud rate) lower than the Bluetooth transmission rate ( maybe 2 Mbps or 3 Mbps with EDR) ?

How can it be transmitted at a higher speed??

Please help I can't figure it out

Thanks in advance
Reference: https://www.robotshop.com/media/files/pdf/rb-ite-12-bluetooth_hc05.pdf

 

[FvM]

HC-05 is build around a programmable Bluetooth transceiver, the achievable USER rate depends on hardware capabilities, crystal frequency and firmware. From the HC-05 user perspective It's not possible to increase the rate above the value implemented in the firmware. Serial Bluetooth adapters with higher supported rate are available on the market.

--- Updated Aug 9, 2020 ---

In additon, recent HC-05 modules are supporting 921.6 and even 1382.4 kBaud.

 

[KlausST]

Hi,

Additionally:
* payload of UART is 80% (10 bits per byte, no protocol)
* But but Bluetooth includes additional data for protocol. So payload may be less

Klaus

 

[FvM]

I'd say, there's no guarantee for a specific continuous data rate on a radio channel. You need to implement hard- or software handshake to prevent data loss. I can tell that 921 kB is typically working.

 

[neonwarrior]

Thanks guys that clarify my question!!