Dragon Beta I/O addresses. $FC00-$FC1F Nothing $FC20-$FC23 68B21 PIA. $FC20 Paralell Printer port. $FC21 CRA $FC22 Keyboard / Keyboard Load. $FC23 CRB $FC24-$FC27 68B21 PIA. $FC24 Mouse port, and Disk select lines, bit 7 controls HALT on DMA CPU. $FC25 CRA $FC26 Beeper (bit 0 ?), Character set select (bit 6, connected to top Addr line of char ROM ?), Printer direction control, bit 7, baud rate setting (Bits 1..5). $FC27 CRB $FC28-$FC3F Unknown/Unused. $FC40-$FC43 6551 ACIA. Registers may or may not be arranged in the normal manner. $FC44-$FC5F Unknown/Unused. $FC60-$FC7F Expansion connector, similar to P2 on Dragon 32/64/Alpha. $FC80-$FC81 6845 CRTC, standard register arrangement. $FC80 6845 register to access. $FC81 Data to read/write to reg. $FC82-$FC9F Unknown/Unused. $FCA0-$FCA3 Colour map registers (may not be 4 bytes long). $FCA4-$FCBF Unknown/Unused. $FCC0-$FCC3 68B21 PIA. $FCC0 DAT control, 4 lower bits select active task reg, Bit 6 enables DAT, Bit 7 flags that this is system task. $FCC1 CRA $FCC2 Graphics control port. $FCC3 CRB CB2 = VSYNC from 6845, used to drive system clock. $FCC4-$FCDF Unknown/Unused. $FCE0-$FCE3 WD2797 Floppy disk controler, regs in standard order. $FCE4-$FCFF Unknown/Unused. $FD00-$FDxx Hard disk controler.