nRF51822 SWD does not work at 1.8V

[Harry]

Hi guys. I have a nRF51822 reference design board which is based on low voltage mode circuitry (using 1.8V supply directly). However, my Segger Jlink (SWD) does not work while giving Jlink Vref 1.8V. I am sure my Jlink does support target voltage from 1.2-5V. And it works well if I increase nRF51822 supply voltage above 2.2V.

I thought it was just a simple connection and I couldn't figure out what could be wrong. So please kindly give me some thoughts. Thanks a lot.

[Øyvind Karlsen]

Hi, could you provide a picture of your layout? Also some more information on your JLink, model number etc, would be nice.

Best regards,

Øyvind