nrf52840 can't find the broadcast signal on cell phone

RE: nrf52840 can't find the broadcast signal on cell phone

raintoo — Fri, 04 Jan 2019 03:04:21 GMT

Yep, I'm not described it right. The Preview versions IC were connected internally.

RE: nrf52840 can't find the broadcast signal on cell phone

ketiljo — Thu, 03 Jan 2019 13:55:12 GMT

Good that you solved this. This isn't because of a bug but a change in the design of the IC from the preview version to the production version.

RE: nrf52840 can't find the broadcast signal on cell phone

raintoo — Thu, 03 Jan 2019 10:38:57 GMT

NOW, The problem was solved. I refered to nrf52840 PDK V0.9.0. This version schematic has a bug that has Two identical Designator Pins DEC2 (A18&E24 ). E24 was the Pin DEC6 in fact ,and must be connected to Pin B5(DEC4) ,because E24 was radio supply. I've had a headache for a week because of this problem. THX

RE: nrf52840 can't find the broadcast signal on cell phone

ketiljo — Wed, 02 Jan 2019 13:31:21 GMT

What's the CL value of the 32 MHz crystal you're using? The value of the load caps must be set according to the CL value. The formula is Ccap = 2 * CL - Cpin, where Cpin is 4 pF.

For a 8 pF crystal, the load caps should be 12 pF each. Also check that the tolerance (stability and temperature) is less than 40 ppm.