Current consumption for bluetooth mesh using PCA10056

[Rosa]

Hi, 

I'm currently doing a current consumption test for bluetooth mesh using PCA10056. I want to label the plot like the ones in Online Power Profiler, but it turns out I'm really unfamiliar with what states bluetooth mesh has (for example, Pre-processing, Radio TX, Radio switch ...). Are there any documents that I can read to have a better understanding of this? 

I just started learning the bluetooth related stuff, I'm sorry if the question sounds stupid. Hoping you guys can help me with that. 

Here attached one plot I got, can someone tell me if it looks reasonable or not? Thanks in advance

[bjorn-spockeli]

I am afraid that we do not have any online power profiler for Bluetooth Mesh node.

A Bluetooth Mesh device will sent packets like a regular Bluetooth Low Energy device, i.e. on 3 separate channels back to back. However, as opposed to regular Bluetooth Low Energy devices, a Bluetooth Mesh node will usually keep the Radio in RX mode the majority of the time. So, if you plot the current consumption you will have a constant current draw corresponding to the NRF52840's Radio RX current. 

I cant see any current numbers in the attached plot.

Best regards

Bjørn

[Rosa]

Hi,

Thank you for the reply.

I actually redid the test last week, I'm using nRF52840, with DCDC off. Here's the plot and data I got. I noticed that when I probe the server board using the light_switch mesh example, I only had one Tx-Rx cycle (instead of 3 as you mentioned). Not sure what's the reason for that. Could you take a look at the graph and the data, and please let me know if I'm doing anything wrong? Thank you thank you.

	State	Time[ms]	Current[mA]
1	Always radio on		12
2	Pre-processing and Standby	4	4
3	Radio preparation	0.6	10
4	TX	0.4	15
5	TX to RX transition	0.6	10
6	RX	0.2	14
7	Post-processing and Standby	7	0
8	Always radio on		12

[bjorn-spockeli]

The Mesh stack does not use the SoftDevice to send advertisment packets, it uses a TimeSlot, so you wont be able to map the states of regular BLE advertising to Mesh advertising. The typical RX current for the NRF52840 RADIO in RX mode is listed as 11mA and the TX current at 0dBm TX power is 10.6mA see this. So the current looks OK. 

[Rosa]

Thank you very much!