BLE_833M_Issues

[sreenathsv]

We are using the Fanastel BC833M (bRF52833) module in our system which uses the BLE interface to communicate with a mobile device.
The device is a battery(3V coin type) operated one and has a sensor (I2C interface) along with BC833M,  which reads the sensor value and through BLE sends it to a mobile device in a predefined time interval.
The device needs to be in SLEEP mode during NOP.


 
We need two clarifications on BLE

1. Regarding the BLE pairing and timeout -
 
   What is the maximum time period in which we can keep the BLE alive in SLEEP mode? Our requirement is to send the sensor data at every 30 minutes interval.

2. Current Consumption during sleep mode when the BLE is connected.
 Our scenario - The device sends the data via BLE at around 10 sec intervals and the rest of the time the device is in SLEEP mode.

 Our observation -
   When the device is in sleep mode we see a current consumption of around 10mA for a duration of 1 ms. This repeats around every 48- 50 ms .

We suspect it has to do something with the BLE . Please help us understand this scenario and observation and how to avoid this current consumption?

[Kazi Afroza Sultana]

Hello,

I have been looking at your issues. Sorry for the late reply as the case arrived in weekend. I will come back to you soon.

Thanks.

Best Regards,

Kazi Afroza Sultana

[Kazi Afroza Sultana]

Hello,

1. Regarding the BLE pairing and timeout -
 
What is the maximum time period in which we can keep the BLE alive in SLEEP mode? Our requirement is to send the sensor data at every 30 minutes interval.

The maximum connection interval is 4 seconds, but it is possible to set slave latency high to allow the peripheral device to sleep for much longer periods. Note that this will affect latency in the incoming direction, as the central can only expect the peripheral to listen for packets on the events when slave latency are reached. Peripheral are allowed to send data on every connection event.

2. Current Consumption during sleep mode when the BLE is connected.
 Our scenario - The device sends the data via BLE at around 10 sec intervals and the rest of the time the device is in SLEEP mode.

 Our observation -
   When the device is in sleep mode we see a current consumption of around 10mA for a duration of 1 ms. This repeats around every 48- 50 ms .

We suspect it has to do something with the BLE . Please help us understand this scenario and observation and how to avoid this current consumption?

10mA is quite high current when device is in sleep mode. You can check the current consumption for different modes here https://infocenter.nordicsemi.com/topic/ps_nrf52840/_tmp/nrf52840/autodita/CURRENT/parameters.i_sleep.html?cp=4_0_0_4_1_0_0 

Have you initialize LFXO of your module? 

Thanks.

Best Regards,

Kazi Afroza Sultana