Hi,
I have 2 pins with PULL_UP in sense mode and when i use sd_power_system_off() i measure 25mA current, which is higher than when my system is on (around 10mA)!! How is that possible? Any advice?
nrf_gpio_cfg_sense_input(14, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
nrf_gpio_cfg_sense_input(15, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
if(nrf_gpio_pin_read(15) != 0 && nrf_gpio_pin_read(14) !=0)
{
APP_ERROR_CHECK(sd_power_system_off());
}
Hi
Check out the power-down examples on Nordic's Github. They are good for testing current consumption. Also make sure you follow the current measurement guidelines given in the User Guide for your development/evaluation kit, in order to get a valid current measurement. Expected current consumption in System On low power mode in the system-on-wakeup-on-gpio example is 2.6uA. Expected current consumption in System Off low power mode with no RAM retention is 0.6uA. To test the current consumption, you should have all GPIO's disconnected as well as the debugger. To disconnect the debugger on the evaluation kit, put SW4 switch to OFF.
More guidelines to lower current consumption are listed on this thread.
Upadate 7.10.2014 Remember to power-reset the nRF51 after you flash/download your code. Alternatively, you can use nrfjprog.exe (part of the nrf51-Tools package) and do a pin reset from the command line with "nrfjprog --pinreset", which will have the same effect. The reason is that after you flash the nRF51 it will be in debug mode which consumes high current. When you power-reset the chip it will enter normal mode with normal current consumption. When you are in debug mode and enter System Off mode, it will in fact enter emulated System Off mode which is also high current. For more details, read nRF51 Series Reference Manual v2.1, section 10.1.2
A few customers that have their own PCB have experienced high current consumption because the nRF51 has entered debug mode after a power-reset. The reason for this is usually noise on the SWDCLK pin. To stay in normal mode the SWDCLK pin must be held low at all times, as described in nRF51 Series Reference Manual v2.1, section 10.1.1.
On the first hardware revision of nRF51, an external pulldown resistor was needed on the SWDCLK pin. On the second revision the resistor is not needed as it is present internally on the nRF51 (Look at the PCN-082 document for documentation on different nRF51 hardware versions). However, a few customers have applied also an external pulldown resistor on the second revision to make the pulldown stronger. These customers were experiencing some signal noise on their PCB, causing a spike on the SWDCLK line and putting the nRF51 therefore into debug mode. We have tested 470ohm external resistor on the SWDCLK pin and that has proven to be good for most programmers/debuggers, they can still drive the SWDCLK line.
Hi
Check out the power-down examples on Nordic's Github. They are good for testing current consumption. Also make sure you follow the current measurement guidelines given in the User Guide for your development/evaluation kit, in order to get a valid current measurement. Expected current consumption in System On low power mode in the system-on-wakeup-on-gpio example is 2.6uA. Expected current consumption in System Off low power mode with no RAM retention is 0.6uA. To test the current consumption, you should have all GPIO's disconnected as well as the debugger. To disconnect the debugger on the evaluation kit, put SW4 switch to OFF.
More guidelines to lower current consumption are listed on this thread.
Upadate 7.10.2014 Remember to power-reset the nRF51 after you flash/download your code. Alternatively, you can use nrfjprog.exe (part of the nrf51-Tools package) and do a pin reset from the command line with "nrfjprog --pinreset", which will have the same effect. The reason is that after you flash the nRF51 it will be in debug mode which consumes high current. When you power-reset the chip it will enter normal mode with normal current consumption. When you are in debug mode and enter System Off mode, it will in fact enter emulated System Off mode which is also high current. For more details, read nRF51 Series Reference Manual v2.1, section 10.1.2
A few customers that have their own PCB have experienced high current consumption because the nRF51 has entered debug mode after a power-reset. The reason for this is usually noise on the SWDCLK pin. To stay in normal mode the SWDCLK pin must be held low at all times, as described in nRF51 Series Reference Manual v2.1, section 10.1.1.
On the first hardware revision of nRF51, an external pulldown resistor was needed on the SWDCLK pin. On the second revision the resistor is not needed as it is present internally on the nRF51 (Look at the PCN-082 document for documentation on different nRF51 hardware versions). However, a few customers have applied also an external pulldown resistor on the second revision to make the pulldown stronger. These customers were experiencing some signal noise on their PCB, causing a spike on the SWDCLK line and putting the nRF51 therefore into debug mode. We have tested 470ohm external resistor on the SWDCLK pin and that has proven to be good for most programmers/debuggers, they can still drive the SWDCLK line.
You should only use sd_* functions if you have already enabled the Softdevice. Have you already enabled the softdevice? Do you measure normal current consumption of 0.6uA in System Off with the unmodified example? If so, that will assume that you are measuring correctly.
to be honest the biggest question is not even in the number, but why when I power MCU off the whole system consumes more? on my board MCU is powered by default, but the rest of the board is disconnected via FET and I checked that the FET is off when MCU is sleeping.