Why I can get always 3.0 volts VDD_nRF, could not be regulate on PCA10.056DK

[FrankBi]

Why I can get always 3.0 volts VDD_nrf, could not be regulate on PCA10.056DK. it seems work at high voltage modes.

Where shall I check? 

Thanks a lot.

[Jørgen Holmefjord]

Hi,

The voltage can only be regulated when the chip is powered in high voltage mode, as described in GPIO levels:

"In normal voltage mode, the GPIO high level equals the voltage supplied to the VDD pin. In High Voltage mode it equals the level specified in register REGOUT0."

If the DK is powered by the J2 USB port (Interface MCU USB port), the power supply is regulated to 3.0 V by an on-bord regulator. The chip is then powered in normal voltage mode. If you want to control the REGOUT0 voltage, you need to power the board from nRF_USB port, or External supply.

Best regards,
Jørgen

[Jørgen Holmefjord]

You can still use the on-board J-Link debugger. Connect both USB cables, set the nRF Power Source switch to "USB", and power on the board.

The debugger should now work as normal, while the board is powered by the nRF_USB 5V power domain.