NRF52832 power leakage

Question

We use NRF52832 in the remote control of the car。 We measured the average current of power consumption at about 1uA.Every 300ms, the current curve bounces to the transient current of 100uA, which we suspect is caused by charging and discharging of the DEC4 decoupling capacitor.We used the power supply of CR2032 to make 2000 samples. 10% of the samples ran out of battery power one month after they appeared. Theoretically, the battery could survive two years without changing.We did not initialize the idle pins, including NFC pin.I don't know what caused our power consumption. The real-time current of the sample retest was normal 1UA. We used SPIS, if configured "nrf_spis_pins_set(NRF_SPIS1,SPI_CLK_PIN,SPI_MOSI_PIN,NULL,SPI_CS_PIN)" This is going to affect the control of idle IO and I don't know what's wrong with the configuration。We also used PPI, mapped timer interrupt events, and GPIO rolloff。"nrf_power_system_off "The PPI needs to be turned off before the function, otherwise the power cannot be reduced. 
 
 “nrf_gpio_cfg(LED_RED, NRF_GPIO_PIN_DIR_INPUT,NRF_GPIO_PIN_INPUT_DISCONNECT,NRF_GPIO_PIN_PULLUP,NRF_GPIO_PIN_S0S1,NRF_GPIO_PIN_NOSENSE);” I don't really understand what NRF_GPIO_PIN_INPUT_DISCONNECT means,When I set pullup and disconnect ,the LED is off. set pulldown and disconnect the light is on . 
 According to the block diagram, shouldn't the light be off as long as I set it off, no matter whether I pull it up or down?

hmolesworth · Answer

The nRF52832 data sheet is incorrect, and the drawing you show is also incorrect. The pull-up and pull down resistors are applied to the port pin regardless of whether the port is set as input or output or unconnected. This means that the internal pull-down supplies power to the LED even if set to Input and Disconnect . I spent some time proving this. The answer to disable the LED leakage is to turn off the pull-down by using PULLNONE . 
 Note LEDs vary a lot; some might appear lit and others not; the pull-up or pull-down are about 13k, but the LED voltage drop varies from part to part and of course the coin cell voltage changes depending on pulse load and recovery time. What capacitance is used as a reservoir on the coin cell, and is this capacitor ceramic or Tantalum? If ceramic, what voltage rating is the capacitor? It matters .. 
 Also what level of illumination is directed at the LED when installed, eg from a car light other than the LED or sunlight? Maybe show the circuit schematic. You can test the illumination level issue; shine the brightest LED torch you can find at the assembly, particularly the LEDs, and see if the measured leakage changes. 
 SPIS should not have pull-ups enabled, except perhaps on /CS if the driver is expected to be disconnected. If there are issues with insufficient pin drive on SPIS the master could be thrashing the slave due to bus errors; just like leaves in sunshine this can exhaust a battery. Some guard timer might help, one SPIS request accepted every minute .. any pin left high or with pull-up enabled while a connected device powers down will try to phantom power the connected device.