Advantech PCI-1751U, User Manual

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PCI-1751U User Manual 2
Chapter 1 General Information
1.1 Introduction
The PCI-1751U is a 48-bit DI/O and counter/timer card with Universal
PCI bus. It provides you with 48 bits of parallel digital input/output as
well as 3 timers. It emulates mode 0 of the 8255 PPI chip, but the buff-
ered circuits offer a higher driving capability than the 8255.
The card emulates two 8255 PPI chips to provide 48 DI/O bits. The I/O
bits are divided into six 8-bit I/O ports: A0, B0, C0, A1, B1 and C1. You
can configure each port as either input or output via software. The dual
interrupt handling capability provides users the flexibility to generate
interrupts to a PC. A pin in the connector can output a digital signal
simultaneously with the card's generating an interrupt. This card uses a
high density SCSI 68-pin connector for easy and reliable connections to
field devices.
Two other features give the PCI-1751U practical advantages in an indus-
trial setting. When the system is hot reset (the power is not turned off)
the PCI-1751U retains the last I/O port settings and output values if the
user has set jumper JA1 to enable this feature. Otherwise, port settings
and output values reset to their safe default state, or to the state deter-
mined by other jumper settings. The PCI-1751U's other useful feature is
it supports both wet and dry contacts, allowing it to interface with other
devices more easily.
1.1.1 Numbering Convention
All numbers given in this manual are in decimal format unless specifi-
cally noted otherwise. In particular, where a register address is given as
(Base + 32), the decimal number "32" should be added to the base value.
1.1.2 Features
• 48 TTL level digital I/O lines.
• Emulates mode 0 of 8255 PPI
• Buffered circuits provide higher driving capability
• Interrupt handling
• Interrupt output pin for simultaneously triggering external devices with
the interrupt