%import textio

main {

;   $1F9C0 - $1F9FF 	PSG registers

    sub start() {
        txt.print("tone")

        uword freq = 1181
        cx16.vpoke(1, $f9c0, lsb(freq))
        cx16.vpoke(1, $f9c1, msb(freq))
        cx16.vpoke(1, $f9c2, %11111111)     ; volume
        cx16.vpoke(1, $f9c3, %11000000)     ; triangle waveform
    }
}