Establish connection between “LE Coded PHY” Central and 1Mbps Peripheral

[beemavishnu]

Hello,

 

I am using nRF52840, SDK_16.0.0, S140 SoftDevice and Segger 4.16 for flashing the image. I am using ‘ble_app_blinky’.

 I have few queries on “LE Coded PHY”, 2Mbps & 1Mbps combinations.

 

1) If my Peripheral is “LE Coded PHY”, then my Central should be in “LE Coded PHY” to receive the packet. Is this assumption correct ?

 

2) I have gone through few documents and it is mentioned as below

a) If my Central is “LE Coded PHY”, whether it can receive Advertisement packets from Peripheral with 1Mbps.

b) If my Peripheral with 1Mbps tries to connect to Central with “LE Coded PHY”, once connection established, whether Central can change to 1Mbps dynamically.

 

My use case is, I have a Central with “LE Coded PHY” and Peripherals where few are with “LE Coded PHY” and few are with 1Mbps. Always my central will connect only one peripheral at a time. So in this case whether Central with “LE Coded PHY” can establish connection to 1Mbps Peripheral.

 

Thanks & Regards

Vishnu Beema

[Simonr]

Hi Vishnu

1. Correct, a central scanning on Coded PHY will only be able to see and connect to Coded PHY devices, and peripherals advertising on Coded PHY will only be visible/connectable to Coded PHY scanners.

2.
a) No, it can not. The primary channels in Coded PHY only contain information that tells the scanning device it is a Coded PHY advertisement, and the actual advertising data is in the extended advertising on its secondary channels.

b) Please check out our long-range blog post, which explains very well how you can advertise/connect in the 1Mbps PHY and change to Coded PHY to keep transmitting long-range.

Best regards,

Simon

[beemavishnu]

Hi Simon,

In the long-range blog, both boards are switched from 1Mbps to Coded PHY.

Whereas in my scenario, whether Central can scan both 1Mbps and Coded PHY advertisement packets in primary channels parallel. I mean, during scanning, whether Central can switch between Coded PHY and 1Mbps and scan both 1Mbps and Coded PHY advertisement packets at a time ?

I am trying to understand below statement from my previous snapshot.

"This means that a central must use the 1M PHY or coded PHY when initially searching for peripherals that are sending out advertising packets."

Thanks & Regards

Vishnu Beema

[Simonr]

No, it can not switch between the two PHYs while scanning, and it can not detect 1Mbps advertisements while scanning in Coded PHY, and vice versa. What you can do, is to scan for X amount of time in 1Mbps, then stop advertising, switch to Coded PHY, and then start scanning again on the Coded PHY layer.

Best regards,

Simon

[beemavishnu]

Thank you Simon, for your inputs.

Let me check on Central side, on how to switch between Coded PHY and 1Mbps and the scan for x amount of time. During scanning, may be I need to use RTC / Timer to switch between Coded PHY and 1Mbps. Once connected need to stop RTC / Timers.

Is my above approach fine. If not any better suggestions please.

Thanks & Regards

Vishnu Beema

[Simonr]

Yes, this seems like a good approach to me.

Best of luck and regards,

Simon