Hi. I'm making a product with 4 capacitative touch buttons using the MSP430G2553. I can measure a signal when holding a probe connected to a scope above the touch-pads. Roughly 2.5-3MHz. Seems to not be there further away, but I don't have very sophisticated equipment/test environment. The product is not EMC-tested yet, but we'll have to do it. I wonder if there is a document on experience with cap-touch's effect on EMC and if this is generally an issue or if it's not a problem. Are there special things I will have to do to make sure it's EMC compliant? I've got a square-pattern ground-plane under the touch-buttons. (as you realize, I'm not an EMC engineer and obviously need help from one later on).
It might be that this signal comes from something else, such as other functions in the MSP430. If the cap touch sensor really just charges and discharges the caps a few times for every button-check, then I would guess this shouldn't be the problem. But the question would be good to get an answer to anyway. Does Cap-touch typically have any impact on EMC testing?