Programming blank nRF52 ic ble issue - crystal issue

[Dajgoro Labinac]

Hi

Last year I got a nRF52 devboard and I modified the ble uart peripheral example to flash a led depending on what it recieves from nRF uart app. It all worked fine(after some forum consulting) so I decided to try making my own version of the devboard (custom pcb) with some extra features. Once the PCB arrived, I got it working, except the ble part. I tried flashing softdevice and did everything as on the devboard, nothing helped. I tried removing the nRF52 mcu from the nRF devboard and soldering a fresh IC that I got from mouser. Same problem, ble now won't work on the devboard either. Then I ordered new devboards, repeated the same flashing process and they work just fine. I can't figure out whats wrong here, can somebody write steps for programming a blank ic from scratch, just in case I'm doing something wrong.

[FormerMember]

Okay, I see.

1. Do you have a lot of ground on your PCB?

2. The load capacitors for the 32 MHz crystal you are using, did you calculate the their value with respect to the crystal specification, using the formula in the tutorial I linked to? Wrong value on those capacitors will lead to wrong frequency of the crystal, which again will lead to wrong carrier frequency in the radio.

[Dajgoro Labinac]

1. Yes, I took care to leave as much ground plane as I could, and stitch it where is possible.
2. I copied the capacitor values from the devboard schematic, which might be the issue when using another crystal. I kinda bodged the smaller smd crystal on my pcb so I don't want to experiment on it anymore. I will solder a fresh PCB and try putting different capacitor values.