Advantech PCI-1739U Manual de usuario descargar pdf (Pagina 37)

27 Chapter 4

4.2.1 Interrupt Function of the DIO Signals

The I/O pin (PC00) can be used to generate hardware interrupt. A user

can program the interrupt control register (Base + 8) to select the interrupt

sources. Refer to "Interrupt Function" in this chapter for details about

interrupt control.

4.2.2 Input/Output Control

A control word can be written to a port's configuration register (Base + 3)

to set the port as an input or an output port, unless the ports are set as out-

put ports via switches (refer to Section 3.1, Switch Settings). The follow-

ing table shows the format of a control word.

Table 4.1: Bit map of port configuration register

D7 D6 D5 D4 D3 D2 D1 D0

-- -- -- PortA

0: output

1: input

Port C

higher bits

0: output

1: input

-- PortB

0: output

1: input

Port C

Lower bits

0: output

1: input

Note: A control word has no effect if the corresponding

port is set as an output port by Switch.

Warning! Before setting any port as an output port via soft-

ware, make sure that a safe output value has

also been set. An output voltage will appear at

the pins immediately following the control word

taking effect. If no output value was specified, the

value will be indeterminate (either 0 or 1), which

may cause a dangerous condition.

1 2 ... 32 33 34 35 36 37 38 39 40 41 42 ... 45 46

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Advantech PCI-1739U Manual de usuario Pagina 37