Adlink PCI-8554 Manual do Utilizador descarregar pdf (Página 31)

Getting Started

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2.13 Debounce System

The debounce system is used to eliminate the affects of bounce

phenomenons. If an external clock is used, user can set JP1 ~ JP11 to

select, whether or not to used the debounce system. If the debounce

system is used, the debounce output signal will be in the same state as

the input only if the input signal maintains the same state for four DB_CLK

cycles, otherwise the input signal will be treated as a glitch and the

debounce output signal will maintain its present state, figure 15 illustrates

how to set these jumpers, figure 16 illustrates how to select the DB_CLK.

Figure 17 illustrates the basic timing of the debounce system. (Note:

DB_CLK can’t be higher than 2MHz).

ECK n

ECLK n

debounce

system

DB_CLK

JP n

n=1~10

EXTIN

EINT

debounce

system

DB_CLK

JP11

Figure 15: Structure of JP1 ~ JP11

2MHz

DB_CLK

COUT11

select by function

"_8554_SET_DBCLK"

Figure 16: Clock Source of DB_CLK

1 2 ... 26 27 28 29 30 31 32 33 34 35 36 ... 66 67

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Adlink PCI-8554 Manual do Utilizador Página 31