you probably would not be able to achieve 477 Khz with the tone library.
However, pins 2 and 3 are capable of toggling at 2.9 Mhz when using fastGpioSCDigitalWriteDestructive()
if you want something simpler you can use fastDigitalWrite()
while(1)
{
fastDigitalWrite(3, HIGH);
fastDigitalWrite(3, LOW);
}
produces a 655 Khz waveform. so you can tweak this a bit to get something close to 477khz.
Do note however that it will not be 100% accurate since the sketch is not running in a real time system.
ToneAC is not supported on the Galileo at all.