RE: nRF51288 custom board cannot be discovered

jtrovato — Wed, 15 Jun 2016 23:41:05 GMT

What was the outcome of this problem? I am experiencing the same issue (code running but not able to be discovered), but used the reference layout.

RE: nRF51288 custom board cannot be discovered

FormerMember — Fri, 13 Jun 2014 14:44:47 GMT

I have updated my answer to answer you question.

RE: nRF51288 custom board cannot be discovered

Michal Zacharias — Fri, 13 Jun 2014 14:09:48 GMT

Well that will be probably the problem. I didn't even know about the reference layout :( Will your reference design work with 0805 or 0201 SMD components?

RE: nRF51288 custom board cannot be discovered

FormerMember — Fri, 13 Jun 2014 13:15:05 GMT

The schematic looks good, the only thing that is missing is a pi-network for the antenna, for matching the antenna to 50 Ohm, see this post regarding why matching to 50 Ohm. However, that should only decrease the range.

The crystal also seems to be fine, at least with respect to the given information, frequency tolerance and load capacitance. The requirements for the 32 MHz crystal can be found in the nRF51822 product specification, chapter 8.1.3. Therefore, I don't think the crystal is the root of the problem.

How did you do the layout? Did you follow our reference layout? In the RF part of the layout, the layout should be a copy of our reference layout. This means that all component values, distances, and relative placement of the components with respect to each other should be the same as in our reference layout. In addition, it is also important to have a lot of via holes. Each grounded component in the matching network should preferably be grounded with at least tow via holes. For where to place the via holes, see our reference layout.

In the RF part of the layout (the components between the chip and the antenna), the component size has to be the same as in our reference layout, 0402. The reason for this is the high frequency, 2.4 GHz.

The reference designs for the nRF5822 can be downloaded from the nRF51822 webpage in the "downloads" tab.

If you don't want to upload the layout here, you can create at support case in the Nordic techinical support system, for a review. If you create a support case, you should upload both schematic and layout (gerber or altium files).