This is an old revision of the document!

Output Ports

Port Number (hex)	Equate	Function	Notes
0	COL0R	Color Register 0 (Right)
1	COL1R	Color Register 1
2	COL2R	Color Register 2
3	COL3R	Color Register 3
4	COL0L	Color Register 0 (Left)
5	COL1L	Color Register 1
6	COL2L	Color Register 2
7	COL3L	Color Register 3
8	CONCM	Consumer/Commercial mode (i.e., low- or high-resolution)	Bally Arcade may only operate in consumer/low-resolution mode
9	HORCB	Horizontal Color Boundary, BG Color	HCB (bits 0–6), BG (bits 6–7)
A	VERBL	Vertical Blank Register	# of vertical lines (x 2) to be used for screen update (c.f., SETOUT)
B	COLBX	Color Block Transfer
C	MAGIC	Magic Register
D	INFBK	Interrupt Feedback
E	INMOD	Interrupt Enable and Mode
F	INLIN	Interrupt Line
10	TONMO	Tone Master Oscillator
11	TONEA	Tone A Frequency
12	TONEB	Tone B Frequency
13	TONEC	Tone C Frequency
14	VIBRA	Vibrato/Tremolo
15	VOLAB	Tone C Volume, Noise Modulation Control
16	VOLC	Tone A Volume, Tone B Volume
17	VOLN	Noise Volume
18	SNDBX	Sound Block Transfer
19	XPAND	Expander Pixel Definition

Port Descriptions

INMOD ($E)

Interrupt Enable and Mode/Vertical Line Feedback. On write, this register enables interrupts and determines the interrupt mode of each. On read, this register contains the vertical line number that a Light Pen Interrupt was received on (not used in WOW). Bit 3 of the Interrupt Enable port (0x0E) when set enables line interrupts, while bit 1 of the same register enables the Light Pen interrupt.

Headline ($F)

Interrupt Line/Horizontal Address Feedback. On write, this register sets the scan line number on which to generate a line interrupt back to the Z80. On read, this register contains the horizontal address (i.e., position in the line) that a Light Pen Interrupt was received on.

[NM:106, 143, source listing 5] Reference: Wizard of Wor arcade disassembly