ADLINK PCI-8554 - Manual (Page 11)

Introduction •1
1
Introduction
cPCI/PCI-8554/R is a general-purpose counter / timer and digital I/O card.
The card is designed with four 8254, a programmable interval
timer/counter chip, totally, providing twelve 16-bit down counter or
frequency dividers. Three different types of interface are available: PCI
(PCI-8554), CompactPCI (cPCI-8554), and CompactPCI with rear I/O
connection (cPCI-8554R) for various platforms and applications.
The card has multi-configurations. Its counters can be set in an
independent or cascaded configuration. The gate controls for the counter
can come from either the internal default enable signal or from external
sources. The clock source of the counters can be set from an internal or
external clock source, when an external clock source is used, users can
configure the jumper as to disable or enable the debounce function.
The card also provides digital input and output ports. There are 8 digital
output and 8 digital input channels, which can be used to control or
monitor external devices.
The cPCI/PCI-8554/R provides an interrupt signal, which is generated by
the counter output. External interrupt signals can also be used. The
interrupt can be used for watchdog timers or others applications. The
maximum interrupt time interval can be 536 seconds.
The I/O signals are provided via the 100-pin SCSI-II connector. Figure 1
shows the functional block diagram of the cPCI/PCI-8554/R. The
cPCI/PCI-8554/R uses ASIC PCI controller to interface the board to the
PCI bus. The ASIC fully implements the PCI local bus specification Rev
2.1. The BIOS software automatically controls all bus relative
configurations, such as base memory and interrupt assignment. This
removes the burden of searching for a conflict, which can be very time
consuming and difficult with some bus standards.