Advantech PCI-1751U Instrukcja Użytkownika Pobierz pdf (Strona 13)

9 Chapter 2

2.3.4 Select Clock Source of Timers and Counter

Jumpers JP1, JP2 and JP3 are used to select the clock source of Timer 0,

Timer 1 and Counter 2, respectively. Short the upper two pins of the

jumpers to select an external clock source, or short the lower two pins to

select an internal clock source. However, the internal clock source of

Timer 1 is connected to the output of Timer 0, so shorting the upper two

pins of JP2 results in the cascading of Timer 0 and Timer 1 as a 32-bit

timer.

Table 2.1: Summary of jumper settings

Names of Jumpers Function description

JPA0, JPA1: Jumpers for ports A0, A1

JPB0, JPB1: Jumpers for ports B0, B1

JPC0L, JPC1L: Jumpers for low nibble

of ports C0, C1

JPC0H, JPC1H: Jumpers for high nibble

of ports C0, C1

Sets port as an output port

Sets port to be software

configurable as input or

output (default)

JP1: Timer 0

P2: Timer 1

P3: Counter 2

Internal counter clock

source

External counter clock

source (default)

JA1

All ports return to state

held just prior to reset

All ports return to default

states (for software-set

ports) or to output port,

output low (for jumper-set

ports

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 37 38

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Advantech PCI-1751U Instrukcja Użytkownika Strona 13