understanding current consumption with twi and s310 softdevice

[tim]

50ms_measure_30ms_other.jpg

Attached is current measured using the s310 softdevice

Every 50ms timer takes a twi measurement, which is a twi 6 byte read followed immediately by a twi 1 byte write

Why does this measurement appear as 2 current peaks rather than one? What do these current peaks represent.

In addition there is a current peak every 30ms. The software does not contain a 30ms timer. What would be this using current every 30ms?

Thx

[Stefan Birnir Sverrisson]

Hi

When in a BLE connection, the radio is enabled periodically even when not transmitting any payload data, it is just to maintain the connection. The radio will consume high current, 10-15mA. So if the BLE connection interval is set to 30ms in your application, that would explain the 30ms peaks.

The same goes for the ANT side of your application, if you are broadcasting or receiving , it will do so periodically, and therefore enable the radio periodically.

So in short, BLE protocol will generate periodic current peaks and ANT protocol will generate additional periodic current peaks with different frequency. Could that be what we are looking at in your attached image?