External Power Supply Problem:

Question

Hello, 
 When I use Debug, the program runs successfully. But when I try to connect with External Power Supply the program is not running, Also Reset is not wokring. Please guide me . 
 Thanks.

Stian Røed Hafskjold · Accepted Answer

Hi, I read through your other posts, and as I understand you are trying to power the whole board with a piezo harvester. The problem is that the external supply header supplies the segger debugger/UART, USB circuitry, level converters, analog switches, ++ in addition to the nRF52 itself. If you want to power the nRF52 only, you will have to do some modifications to the board. Please follow my steps here: 
 
 Cut SB9 
 Cut SB26 (bottom side) (RESET) 
 Cut SB20 (bottom side) (SWDIO) 
 Cut SB21 (bottom side) (SWDCLK) 
 Power the board directly on VDD_nRF as shown in the picture below: 
 Modify the ble_app_beacon application to disconnect all pins (by default the 4 LED pins and the UART TX pins are configured as outputs). Otherwise the rest of the board will be powered through the GPIOs.
 
 Set NRF_LOG_ENABLE to 0 in pca10040/s132/config/sdk_config.h 
 Remove the leds_init() call from the main function.

When flashing the board you will no longer be able to use the on board debugger as normal since the SWD wires are cut. You have two choices (unless you want to re-solder SB20 and SB21 every time you flash the chip): 
 
 Use an external debugger:
 
 Power the board on the External supply header (3V) 
 Short P22 with a jumper 
 Connect the debugger to the Debug in header

Use the on board debugger:
 
 Connect a USB cable 
 Short P22 with a jumper 
 Connect a SWD 10 pin cable between the Debug Out and Debug In headers

External Power Supply Problem:

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