nrf52 Power consumption intermittently high

RE: nrf52 Power consumption intermittently high

FormerMember — Mon, 24 Jul 2017 09:42:41 GMT

With the TIMER running, there should be an additional 250 uA + 70 uA = 320 uA current consumption..

RE: nrf52 Power consumption intermittently high

eq — Thu, 29 Jun 2017 05:25:45 GMT

Update: I have isolated the high current condition (510 uA) to occurring only when I use the SAADC WITH a Timer. If I just initiate a sample capture using nrf_drv_saadc_sample(); with NO Timer, the current stays at 34uA. Is there perhaps some Timer Interrupt that needs to be cleared to prevent this?

RE: nrf52 Power consumption intermittently high

eq — Wed, 28 Jun 2017 14:10:02 GMT

Clock config is below:

nrf_clock_lf_cfg_t clock_lf_cfg = { .source = NRF_CLOCK_LF_SRC_RC, .rc_ctiv = 16, // Check temperature every 4 * 250ms .rc_temp_ctiv = 2, // Only calibrate if temperature has changed. .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_250_PPM, };

// // Initialize the SoftDevice handler module. // SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL);

To be clear, when the board boots up it runs at 34uA. After the system starts communicating with the App and begins taking ADC measurements, thats when it sometimes goes up to 500uA.

RE: nrf52 Power consumption intermittently high

John — Wed, 28 Jun 2017 13:35:43 GMT

@eq - We had a similar issue migrating from the 51 to the 52. Here are a couple of other things I would check: 1) If the HW is set up for DC-DC converter, be sure to enable it. 2) If you are using the TWI look at PAN-89 in the errata 3) There was a note about when clearing Events, read them back to make sure the clear is flushed to RAM before moving on. 4) Make sure to use sd_app_event_wait when idling rather than __WFE

RE: nrf52 Power consumption intermittently high

FormerMember — Wed, 28 Jun 2017 12:55:25 GMT

Which LFCLK source do you use, the internal RC oscillator? If so, what is the calibration interval? Does the interval where the board use 500 uA change if you change the calibration interval of the RC oscillator?