High Current Consumption After I2S

RE: High Current Consumption After I2S

Bill Finger — Mon, 06 Feb 2017 13:32:03 GMT

It was the nRF52; in particular, it was the I2S module. By using low level functions instead of the high level driver, I was somehow putting the module in a state where it drew more current. Interestingly, I was never able to get it out of this state by changing registers in the IDE, which is why it took so long for me to figure it out.

RE: High Current Consumption After I2S

Roger Clark — Fri, 03 Feb 2017 19:48:56 GMT

What was taking the current in this situation, the nRF52 or the external hardware ?

RE: High Current Consumption After I2S

Bill Finger — Fri, 03 Feb 2017 15:52:29 GMT

It turns out that I was leaving the I2S bus in a bad state. Using the nRF driver functions instead of the low level I2S functions solved the problem.

RE: High Current Consumption After I2S

Bill Finger — Thu, 26 Jan 2017 14:33:17 GMT

I haven't run the beacon example. However, I have no reason to believe the amplifier is the issue. I can power it up, configure it, and power it down, and always returns to the same current level. Only after I run I2S through the processor is there a problem. The extra current draw disappears the instant I reset or shutdown the processor. It must be related to processor state.

RE: High Current Consumption After I2S

Roger Clark — Tue, 24 Jan 2017 22:02:59 GMT

Have you just tried running the beacon example on your hardware, and change the advertising period to some big number like 10 seconds.

The beacon is known to take the minimum amount of current when not transmitting, so any other current must being taken by your other components e.g. the amplifier

If the amplifier takes current with the beacon example, its probably worth adding pull-ups or pull downs etc to prevent this happening, and use that as a baseline

RE: High Current Consumption After I2S

Bill Finger — Fri, 20 Jan 2017 15:34:37 GMT

I've reset all the GPIO to their default state (PIN_CNF=2) and that doesn't appear to be it.

RE: High Current Consumption After I2S

Bill Finger — Fri, 20 Jan 2017 13:19:24 GMT

An excellent thought. I am powering down the audio amplifier as per its manufacturer's recommendations, then holding it in reset. If I then reset the nRF52, the current draw immediately drops from the 1.7 mA value to the 0.3 mA value, leading me to believe it is some state in the nRF52.

RE: High Current Consumption After I2S

Roger Clark — Fri, 20 Jan 2017 02:17:43 GMT

Have you isolated whether the current draw if from the nRF52 or from your I2S device (or I presume the output amplifier for the audio). You may need to send a power off command to the I2S device

I have a similar situation with a OLED display, and even sending the power down command didnt reduce the current very much. The only solution in my case was to toggle the reset line on the OLED controller which shut it down completely, but means I have to resend the display config each time I need to use the display :-(