* 1 = Reserved (would access both PSG and 8253 together)
* 2 = RTC (Real-Time Clock) (With PPI.Port C: Bit2=DS, Bit1=AS, Bit0=R/W. So combinations are 2, write address, 4 write data, 5 read data)
* 3 = 8254 8253 (Baudrate/Future Timer) (With address lines A0 and A1 = register selection)
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|3||force video to black