Hello Community,
The PCB project I'm working on is ready to be optimized for production. What I am concerned with today is the electromagnetic compliance of the PCB.
In the attached FCC document below, it details the classifications of Class B computer devices. My PCB will have an nRF52832 built within a module already certified by the FCC to transmit BT, four sensor ICs that all communicate over IIC with the nRF52, and a PMIC with 18650 battery attached on the back of the PCB. From the research I've done, I've determined that the PCB I've built will fall into the "Other Class B digital devices and their peripherals". In order to get verification of compliance with FCC standards Part 15, the device will need to pass general emissions tests.
Designing the device to pass general emissions tests has started with a read of the attached TI document. The document specifies that unused ports on devices should be grounded, shorted ideally, to reduce as much as possible EM emissions during operation. If I employ this, it will obviously carry a risk that if one of those ports were ever driven high for whatever reason, there would be a short that could destroy the device. What would be a good strategy for preventing these grounded ports from being driven high? If I want to employ a watchdog-type system on the device to monitor the grounded ports and shut the port or even the entire device down when necessary, how could I go about doing that?
If there are any individuals here who want to give general advice on how to design a PCB with an nRF52 at its core that will emit as little EM as possible, it would be greatly appreciated!
Ben
