broadcast 256byte

[peter]

Hi All,

I would like to broadcast 256 byte data in one shot every second, any reference in SDK recommend?

Thanks in advance.

**updated at 19 Sep, 2014

Application: 20+ broadcast device(nrf51822-S110), 1 receive device(nrf51822-S120) The broadcast device send 256byte data every minute. The receive device keep receive the data and update the user by uart.

In very beginning, I try to use ibeacon to broadcast data. However the manufacture info can carry only 16byte data, so I am looking for other broadcast method.

[mnhs]

What are the other requirements of your application? I mean network topology, latency, number of communicating nodes, is the application going to be smartphone or PC-enabled etc.

There is a number of possibilities, in fact almost every protocol can be adapted to serve this purpose - your own protocol, Gazell, ANT (burst), BLE etc. It all depends on the other requirements.

[Petter Myhre]

Please edit your question and add some more information. mnhs has some good suggestions.

[Petter Myhre]

When in a connection, the S110 is capable of transmitting 128 kbps, see this. It is capable of transmitting 6 packets in each connection interval, but the S120 is only capable of receiving 1. This means that the S120 can only receive 21 kbps.

You want to 20 devices to transmit 256 bytes, 2048 bits, every second. You require a data rate of 20*2048 = 41 kbps.

So if even if you didn't waste a single connection interval this just would be not possible.

If the S120 was capable of 128 kbps, this wouldn't be the effective data rate since you are juggling 20+ connections.

We are aware of the S120 limitation and we want to remove it.

I can't discuss future release and features, but if you send me a PM telling me where you are localized, I can put you in contact with the Nordic sales team in your region.

[peter]

I had try to change BLE_GAP_ADV_MAX_SIZE from 31 to 63 but it doesn't work.... what approach should I focus? should I continue use advertising approach?

[Petter Myhre]

31 is max, you can't increase it, please see this. You can add 31 additional bytes in a scan response, please see this. I don't think this is possible to do this with broadcasting, it may be possible in a connection, please see my answer below.