BMD-350 Erratic Current Consumption BLE

RE: BMD-350 Erratic Current Consumption BLE

hmolesworth — Fri, 23 Oct 2020 17:23:04 GMT

Me being lazy: m:s == mark:space ratio. If using your voltmeter in the main loop set the output pin high before the sleep instruction and set low after sleep. A voltage near Vdd (typically 3.3 volts) is good, ie asleep most of time. A voltage near 0v is bad, awake most of time. In the scenario you describe you will see both of these

RE: BMD-350 Erratic Current Consumption BLE

Soumyanit95 — Fri, 23 Oct 2020 16:41:39 GMT

Yes I will do some more testing this weekend as well. Btw could you tell me what do you mean by m: s ratio ?hmolesworth

RE: BMD-350 Erratic Current Consumption BLE

hmolesworth — Fri, 23 Oct 2020 16:06:23 GMT

Your engineer is probably thinking feedthrough might be an issue; the nRF52832 is not affected by floating pins left in the default state. Internally these are held (and read) at '0' but without bus loading.

More likely the nRF52 is not properly in sleep. Easy check just toggle a spare pin set as an output either side of the sleep and watch with 'scope or your meter; the m:s ratio indicates the time in sleep.

RE: BMD-350 Erratic Current Consumption BLE

Soumyanit95 — Fri, 23 Oct 2020 13:44:46 GMT

As shown in the schematic, we just have the regulator, BMD-350 and HX-711 on the board and out of them,i had de-soldered the HX711 last week just to observe how the circuit behaves. It was still sometimes consuming high current of 11mA in active state and 8-9 mA in sleep state. This makes me doubt that it is the BMD-350 which sometimes is in a confused state maybe !

We are using nRF5_SDK_15.2.0_9412b96.

I can provide more info to you after a couple of days after debugging some more with our firmware engineer. Is there something specific that we should be looking for while debug logs?

I remember him saying that the unconnected / unused pins are not mentioned in FW at all. Can that be a problem here ? Do we have to pull - up /down the unused GPIO pins ?

RE: BMD-350 Erratic Current Consumption BLE

Edvin — Fri, 23 Oct 2020 12:47:26 GMT

Hello,

Have you tried to disable one and one module at the time from software to see whether you can see what's drawing the power? Have you tried to debug anything?

[quote user=""]out of every 10 attempts on switching on the device, 3-4 times,[/quote]

That sounds like either:

One of the external peripherals are stuck in some state between the resets, or there is something flash dependent that behaves different on every reset. Do you use flash (e.g. peer manager)?

What SDK do you use? Do you see anything interresting in the log?

BR,

Edvin

RE: BMD-350 Erratic Current Consumption BLE

Soumyanit95 — Fri, 23 Oct 2020 11:11:04 GMT

Yes it is not the most elegant option for sure but I am concerned with the general trend over here, don't need a lot of precision. My multimeter Extech EX330 is working fine in the "mA" mode and is able to display the currents in both the active and sleep states. And also functionality wise, the BMD -350 module is working fine , sending data packets which I can view using the nrf app and then stopping packets in sleep. So I suspect that it has something to do with floating pins maybe.

RE: BMD-350 Erratic Current Consumption BLE

awneil — Fri, 23 Oct 2020 10:25:04 GMT

[quote userid="83395" url="~/f/nordic-q-a/67562/bmd-350-erratic-current-consumption-ble"]we wanted to monitor current consumption and hence we connected a multimeter[/quote]

A multimeter is no use for this kind of application.

The current consumption of a BLE radio - like any such radio - is extremely "spiky"; eg,

Multimeters cannot give a meaningful display of such waveforms.