Coin Impulse

Advanced Topic - Coin Impulse & Duty Cycle

Coin Impulse refers to the amount of time a coin active signal is presented for triggering a credit.

Duty Cycle refers to the amount of time from one coin active signal to the next coin active signal.

Some titles require specific conditions for credits to be accepted such as duty cycle & coin impulse.

For example:

Tetris Plus 2 Requires >70mS signal to reliably trigger a credit (50mS will cause credit instability)
Williams Titles (Defender, Joust etc.) require > 500mS duty cycle for each credit to be accepted.

It is also important to note that arcade encoder interfaces may affect coin impulse & duty cycle times.

Mame has a coin_impulse option available for modifying the behavior of the signal presented to trigger a credit.

-coin_impulse [n]

Set coin impulse time based on n (n<0 disable impulse, n==0 obey driver, 0<n set time n).

Default is 0.

Where [n] is the number of frames the signal is presented.

For example:

Title refresh = 60hz

Coin impulse = 6

1 ÷ 60 = 0.0166666'

0.0166666' × 6 = 0.1 seconds (Or 100mS)

Setting coin impulse of 6 on a 60hz title presents a 100mS signal for triggering a credit.

n==0 obey driver will present a signal for as long as the credit input is active.

Obey driver is typically used unless there is a need to set it otherwise.

Usage:

Coin impulse may be set if you are unable to increase the signal time from the credit mechanism.

PENDING