After messing around with the board for most of today I can share how to get the power down to a sensible level. I am currently at ~2uA in deep sleep, 3-4uA in light running (e.g. suspendLoop or delay).
Everyone who was stuck at ~20uA, the problem is there is a QSPI flash chip (P25Q16H) that remains powered when powering down the NRF and does not go into deep sleep itself. This flash chip sits there and draws ~18uA all the time. To put it into deep sleep you need to send the command 0xB9 to it.
#include <Adafruit_FlashTransport.h>
Adafruit_FlashTransport_QSPI flashTransport;
//start bluefruit (this also starts the soft device if you don't start the sd then none of your sd_* calls will do anything
Bluefruit.begin();
//before you put the NRF to sleep put the flash to sleep
flashTransport.begin();
flashTransport.runCommand(0xB9);
flashTransport.end();
//map a pin for wakeup
nrf_gpio_cfg_sense_input(g_ADigitalPinMap[D3], NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
//shutdown
sd_power_system_off();
This will leave the flash in deepsleep next time you wake up the NRF, the command from the data sheet to turn it back on is 0xAB but I haven’t played with it yet. I used the adafruit sdfat fork to send in the qspi commands as it is much simpler than interfacing with the qspi hardware directly.
lib_deps =
adafruit/Adafruit SPIFlash@^4.0.0
adafruit/SdFat - Adafruit Fork@^2.2.1
Deep sleep with flash also in deep sleep:
