https://devzone.nordicsemi.com/f/nordic-q-a/3417/trying-to-use-dev-kit-without-nrfgo-starter-kitHi, I am trying to use the PCA10004 board in a custom application without the use of starter kit. When I burn the nRF51822 chip with my custom program, in my custom hardware everything is working properly. But when I disconnect the segger programmeren-USTelligent Community 13Mon, 11 Aug 2014 07:00:55 GMThttps://devzone.nordicsemi.com/thread/12412?ContentTypeID=1Mon, 11 Aug 2014 07:00:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a284ee90-f5ab-4077-a2cc-9d0d83ca14e4Stefan Birnir Sverrisson<p>Hi John</p> <p>On the first hardware revision of nRF51 (XLR1), a pulldown resistor was needed on the SWDCLK pin. On the second revision (XLR2) the resistor is not needed as it is present internally on the nRF51. However, a few customers have applied also an external pulldown resistor to make the pulldown stronger. These few 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. So having the internal ~12k resistor and the 12k external resistor in paralell is quite ok, although in most cases it would not be necessary to add an external resistor.</p><div style="clear:both;"></div>