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mc6809

Simulator for Motorola 6809 processor and scaffolding for an early 80's Williams arcade console that will run Defender ROMS

How to start a game of Defender

Press 1 for one-player start.

Player keys: Space=Fire, =Thrust, End=Smart Bomb, Enter=Hyperspace, =Reverse, /=Up/Down, 1/2=Start.

Defender operator menu reference

The on-screen labels are generic Williams ones; the descriptions below come from the Defender operator manual. To enter the menu: uncheck Auto-Up, click Reset. To leave: re-check Auto-Up and Advance through to Function 28, then click Advance once more.

Bookkeeping totals (Functions 1-7)

In game-over mode, set the switch to AUTO-UP and depress ADVANCE. The CRT indicates Function 1 and total left-chute coins. Continue ADVANCE through each function. To review a total advanced past, set switch to MANUAL-DOWN and depress ADVANCE.

Function Default Description
1 0 (Total) COINS LEFT
2 0 (Total) COINS CENTER
3 0 (Total) COINS RIGHT
4 0 TOTAL PAID (games)
5 0 (Total Bonus) SHIPS WON
6 0 TOTAL (Play) TIME (minutes)
7 0 TOTAL SHIPS (played)

ADVANCE through to Function 28 (SPECIAL FUNCTION) to return to game-over or zero the totals. With AUTO-UP set:

  • Return to game over — depress ADVANCE.
  • Zero audit totals and return to game over — operate HIGH SCORE RESET to indicate "35" on CRT Function 28, then depress ADVANCE. Observed: this doesn't actually work in this emulator — only the full factory reset (value "45", below) clears audit totals.

Game adjustments (Functions 8-27)

Same entry: AUTO-UP, ADVANCE. Raise the function number with ADVANCE in AUTO-UP, lower it with ADVANCE in MANUAL-DOWN. Raise the value with HIGH SCORE RESET in AUTO-UP, lower it with HIGH SCORE RESET in MANUAL-DOWN. The value left on the CRT is the new setting.

Function Factory Description
8 10000 BONUS SHIP LEVEL (0 = no bonus ships)
9 3 SHIPS PER GAME
10 3 COINAGE SELECT
11 1 LEFT COIN MULT
12 4 CENTER COIN MULT
13 1 RIGHT COIN MULT
14 1 COINS FOR CREDIT
15 0 COINS FOR BONUS
16 0 MINIMUM COINS
17 0 FREE PLAY (set to 1 for free play)
18 0 STARTING DIFFICULTY (0 = LIB; 1 = MOD; 2 = CONS)
19 10 PROGRESSIVE WAVE DIFFICULTY LIMIT (4-25; e.g. 5 = LIB, 10 = MOD, 15 = CONS)
20 1 BACKGROUND SOUND (0 = OFF, 1 = ON)
21 5 PLANET RESTORE WAVE NUMBER
22-27 0 NOT USED

ADVANCE through to Function 28 (SPECIAL FUNCTION) when done, then either:

  • Return to game over — AUTO-UP set, depress ADVANCE.
  • Restore factory settings + zero audit totals (full reset):
    1. Operate HIGH SCORE RESET in AUTO-UP to indicate "45" on CRT Function 28.
    2. Depress ADVANCE — the game returns to audit Function 1.
    3. Set switch to MANUAL-DOWN, depress ADVANCE until Function 28 shows.
    4. Set switch to AUTO-UP, depress ADVANCE.

Resetting high scores

In game-over (attract) mode, depress HIGH SCORE RESET. This clears the high score table and erases entered signatures.

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Simulator for Motorola 6809 processor and scaffolding for an early 80's Williams arcade console that will run Defender ROMS

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