Can't achieve low power with PCA10028

[Lee Daniel Crocker]

I'm trying to measure absolute minimum power consumption of the chip using the PCA10028. I cut SB 9, and applied a very sensitive current measuring device to P22. I'm running the following code (no SD):

int main(void) {
    NRF_POWER->RAMON = POWER_RAMON_ONRAM0_RAM0On << POWER_RAMON_ONRAM0_Pos
                     | POWER_RAMON_ONRAM1_RAM1On << POWER_RAMON_ONRAM1_Pos
                     | POWER_RAMON_OFFRAM0_RAM0Off << POWER_RAMON_OFFRAM0_Pos
                     | POWER_RAMON_OFFRAM1_RAM1Off << POWER_RAMON_OFFRAM1_Pos;
    
    NRF_RADIO->TASKS_DISABLE = 1;
    NRF_POWER->TASKS_LOWPWR = 1;
    NRF_POWER->SYSTEMOFF = 1;
}

I'm consistently measuring 1.8 mA (that's milliamps--1000 times what the specsheet says I should be getting). I've read all the threads here, I'm pressing RESET (is there some other way I should be resetting the chip to get out of debug mode?), SYSTEMOFF mode says it powers down everything, so what am I missing?

Also, the signal I'm getting from the current measurement is jittery at about 3kHz. Is there maybe something on the board waking it up at that rate?

[Michael Dietz]

I wonder if its the interface MCU that is drawing this current. Have you eliminated the possibility of this? I'm really not sure about this so look into it yourself but I think the interface mcu makes it a bit difficult to measure current. it shares the same VCC with the nrf device and I think this is also in the current measure port. but if you look closely on the schematic you should be able to find a VCC_NRF or something like that on a pin out. and maybe try to measure there?