I've been trying to generate a square wave using the tone() function on the Portenta using the Breakout Board. In particular, I am using GPIO pin 5, which only works if I use the alternative pin name of PG_3 as pointed out by @jerteach on Github back in March.
The code compiles and uploads successfully, but all I get are four short red LED blinks followed by four long LED blinks. I take it that tone() is not supported by the Portenta?