Gazell Host forgetting Devices

[Bryan]

In our application, we have two devices that will communicate to a host at a time.  All are nRF51822.  However, the two devices could be swapped out with two new devices to communicate to the same host.

- Only two devices will communicate to the host at any one time.

- The devices will always transmit data on the same pipes (2 and 3).

For example:

1.  Two devices (Device set A) pair to the host and start sending data.

2.  A new user wants to pair their two devices (Device setB) to the host and start sending data.  Device set A are turned off and device set B are turned on and pair to host.

3.  Repeat for device pair C, D, etc.

I am unsure of the best way to implement this functionality.

When the second device set (B) pair to the host, it stores the device info in GZP_PARAMS_STORAGE_ADR.

1.  How many paired devices can the host save before not accepting any more devices?  Or does the host start over-writing older paired devices.

2.  Is the only (or best) way to delete the list of paired devices in the host to reset the host?

Thanks!

[Håkon Alseth]

Hi,

 

1.  How many paired devices can the host save before not accepting any more devices?  Or does the host start over-writing older paired devices.

The host does not store the state of each paired device. The gzp host stores its own "system address" (randomly generated):

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/gzp_02_user_guide.html?cp=8_1_5_5_3#key_ex_stages

 

A device has the option to store its host pairing parameters to flash, which then includes more, as shown above. 

 

2.  Is the only (or best) way to delete the list of paired devices in the host to reset the host?

However, the two devices could be swapped out with two new devices to communicate to the same host.

The information, except the system address, is stored on the device side. Gazell is a device driven protocol in general, star-network topology with the host receiving data from device(s). What it sounds like you want is the opposite, one device to many hosts; which isn't what gazell/GZP was made to do.

If a device is paired, it will store the host's info in either RAM or flash (configurable), and if you re-pair with other hosts, it will append this information to the pairing data-base and point specifically to which host-configuration is currently active.

  

Kind regards,

Håkon