Address Map (PC-8801)

Memory Map

Range	Name	Function
0x8000-0x800F	Interrupt Jump Pointer Table	0x8000-0x8001: / INT7 (RS-232C Ch1 in RS-232C BASIC) 0x8002-0x8003: INT6 (vertical blank) 0x8004-0x8005: INT5 (system clock) 0x8006-0x8007: INT4 / INT3 (user defined) 0x8008-0x8009: INT3 / INT4 (user defined) 0x800A-0x800B: INT2 / INT5 general-purpose I / O port 0x800C-0x800D: INT1 / INT1 (for floppy) 0x800E-0x800F: INT0 / INT2 (for floppy)

Port Writes

Port	Name	Function
0x10	Tab key status	bit 1 set if tab key down; else clear
0xA	Printer data
0x30
0x31	PC-8001 Emulator	Bit8 - background color Bit7 - background color Bit6 - background color Bit5 - Resolution: 320 × 200 if set, else 640 × 200 Bit4 - Screen drawing: draw if set, else do not draw Bit3 - Color: monochrome if set, else indexed color Bit2 - Memory mapping: map 0x7FFF to RAM if set, else ROM Bit1 - Expansion ROM select: map 0x6000-07FFF ROM to N80/N-BASIC if set, else to extended ROM. Set by default.
0x34
0x35
0x52	Background Color	Sets the background color of the screen. The color is an RGB composite. BLUE ON if bit 3 (mask 0x8) set GREEN ON if bit 4 (mask 0x10) set RED ON if bit 5 (mask 0x20) set
0x53
0x54	Toggle Background/Foreground color components	Toggles background and foreground color components on and off if 8-color mode if bit 8 (mask 0x80) set, target is background color, else foreground if bit 7 (mask 0x40) toggle green component GREEN ON if bits 1,2,3 (0x7) set, else OFF else toggle red and/or blue BLUE ON if bit 1,2,3 set, else OFF RED ON if value written / 8 sets bits 1,2,3, else OFF else if monochrome mode, set foreground color BLUE ON if bit 1 set (mask 0x1) RED ON if bit 2 set (mask 0x2) GREEN ON if bit 3 set (mask 0x4)
0x55-0x5B	Palette Write	Writes to the palette. The index written to is the difference between the port number and 0x54. if port 0x31 bit 6 (0x20) set if bit 7 (mask 0x40) toggle green component GREEN ON if bits 1,2,3 (0x7) set, else OFF else toggle red and/or blue BLUE ON if bit 1,2,3 set, else OFF RED ON if value written / 8 sets bits 1,2,3, else OFF else BLUE ON if bit 1 set (mask 0x1) RED ON if bit 2 set (mask 0x2) GREEN ON if bit 3 set (mask 0x4)
0x5C-0x5F
0x5F	Bank Select	Map 0x8000-0xBFFF to a page in ROM
0xE8-0xE9	Japanese Kanji ROM Address	0xE8 (low) 0xE9 (high)
0xEA-0xEB	Chinese Kanji ROM Address	0xE8 (low) 0xF4 (high)
0xF4-0xFB	Floppy Disk DMA (Direct Memory Access system)	8 inch disk 0xF4: control 0xF5: margin control 0xF6: controller status 0xF7: data 5 inch disk 0xF8: control 0xF9: margin control 0xFA: controller status 0xFB: data

0E8H (output) Kanji ROM lower address