nrf51822 with wifi from particle

[artmaster547]

Hi All I want to develop a PCB that has Wifi and BLE capabilities, to do this I would like to use Nordics: NRF51822 or the new NRF528, for the wifi side of things I want to use Particles Photon/P1, can anyone talk me through how I can integrate these two products, can they put in together on this pcbs as separate modules or do these modules need to communicate with each other, i.e. can they use the same antenna?

Kind Regards

Art

[Jørn]

Hello artmaster547

For the nRF5x you should carefully read the sections of the relevant product specification regarding reference schematics and PCB considerations. You can find further guidelines for the nRF51 here and nRF52 here. It is recommended you follow the reference schematic and layout closely.

For the wifi modules mounting you will need to read the product specification for that specific module, or contact particle's support. The P1 module is FCC certified, however according to the FCC document 996369 D01 Module Certification Guide v02 section IX C, you will need to have it recertified as the nRF5x and the P1 module have not been specifically certified together.

While both devices do operate at 2.4GHz it is not recommended to try to connect them together to the same antenna, unless you have a properly designed RF circuit with RF switches to choose which source is feeding the antenna. Each connection would have to be carefully designed to match the antenna, ensure correct filtering and compensate for the impedances you see into the other device due to the switch being non-ideal.

Beyond this, you will have to ensure co-existence between the two. I do not have any personal experience when it comes this. However, the Wifi module seems to have an output power of roughly 15-18 dBm depending on mode. I imagine that can cause quite a bit of noise for the nRF, even if they are not operating in the same channel, so they may not be able to operate simultaneously. If that is the case you will most likely need some communication between them to ensure they do not transmit data while the other is trying to receive data.

You should probably also look into methods of shielding the nRF5x and the P1 from each other on the PCB, if necessary, so they do not interfere with each other's operation.

Best regards

Jørn Frøysa