- Wed Sep 10, 2014 7:05 pm
#174820
I'm investigating using BLE/BT Smart as an RF channel between a controller (a PC/smartphone/tablet/???) and multiple peripherals. The question I have is how many slaves/peripherals can be connected to the master/central at any one time ? This SFE tutorial suggests that number is 7.
https://learn.sparkfun.com/tutorials/bluetooth-basics
Other articles say "No, it's 1 master and 6 slaves". And yet when I try to dig into the spec, I see no mention of any hard limit. Lastly I found one article that says there's no hard limit (per spec), but it's limited by the hardware, or perhaps (my thinking) really the firmware. And I want to be clear, I don't expect any 2 slaves to be "connected" and talking/transmitting to the master simultaneously, but rather that each of N slaves could time share the master on a non-interfering basis. So what's N and why the limit (if there is one) ?
And if N varies ... how can I (? can I ?) tell what that is for any given PC/smartphone/tablet/??? ?
FWIW I note Nordic says of their nRF51822 ...
https://www.nordicsemi.com/eng/Products ... /nRF51822/
... that when using the S120 protocol stack, it's 8 concurrent "connections".
S120 SoftDevice
The S120 SoftDevice is a Bluetooth® low energy (BLE) Central protocol stack solution supporting up
to eight simultaneous Central role connections. It integrates a Bluetooth low energy controller and host,
and provides a full and flexible API for building Bluetooth low energy System on Chip (SoC) solutions.
https://learn.sparkfun.com/tutorials/bluetooth-basics
Other articles say "No, it's 1 master and 6 slaves". And yet when I try to dig into the spec, I see no mention of any hard limit. Lastly I found one article that says there's no hard limit (per spec), but it's limited by the hardware, or perhaps (my thinking) really the firmware. And I want to be clear, I don't expect any 2 slaves to be "connected" and talking/transmitting to the master simultaneously, but rather that each of N slaves could time share the master on a non-interfering basis. So what's N and why the limit (if there is one) ?
And if N varies ... how can I (? can I ?) tell what that is for any given PC/smartphone/tablet/??? ?
FWIW I note Nordic says of their nRF51822 ...
https://www.nordicsemi.com/eng/Products ... /nRF51822/
... that when using the S120 protocol stack, it's 8 concurrent "connections".
S120 SoftDevice
The S120 SoftDevice is a Bluetooth® low energy (BLE) Central protocol stack solution supporting up
to eight simultaneous Central role connections. It integrates a Bluetooth low energy controller and host,
and provides a full and flexible API for building Bluetooth low energy System on Chip (SoC) solutions.