INDUSTRIAL I/O PACK SERIES APC8620/8621 PCI BUS CARRIER BOARD
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IP Logic Interface
The IP logic interface is also implemented in the logic of the
carrier board’s FPGA. The carrier board implements ANSI/VITA
4 1995 Industrial I/O Pack logic interface specification and
includes five (three for APC8621) IP logic interfaces. The PCI
bus address and data lines are linked to the address and data of
the IP logic interface. This link is implemented and controlled by
the carrier board’s FPGA.
The PCI bus to IP logic interface link allows a PCI bus master
to:
•
Access up to 64 ID Space bytes for IP module identification
via 8-bit or 16-bit data transfers using PCI bus.
•
Access up to 128 I/O Space bytes of IP data via 8-bit or 16-
bit data transfers.
•
Access IP module interrupt space via 8-bit or 16-bit PCI bus
data transfers.
•
Respond to two IP module interrupt requests per IP module.
Carrier Board Clock Circuitry
A 16MHz clock is divided down by a clock driver to obtain the
IP module 8MHz clock signals. Separate IP clocks are driven to
each IP module. All clock lines include series damping resistors
to reduce clock overshoot and undershoot.
When an IP module places data on the bus, for all data read
cycles, any undriven data lines are read by the PCI bus as high
because of pull-up resisters on the carrier board’s data bus.
PCI Interrupter
Interrupts are initiated from an interrupting IP module.
However, the carrier board will only pass an interrupt generated
by an IP module to the PCI bus if the carrier board has been first
enabled for interrupts. Each IP module can initiate two interrupts
which can be individually monitored on the carrier board. After
interrupts are enabled on the carrier board via the Interrupt
Enable Bits (see section 3 for programming details), an IP
generated interrupt is recognized by the carrier board and is
recorded in the carrier board’s Interrupt Pending Register.
A carrier board pending interrupt will cause the board to pass
the interrupt to the PCI bus provided the Interrupt Enable bits of
the carrier’s Status Register have been enabled (see section 3 for
programming details). The PC interrupt request line assigned by
the system configuration software will then be asserted. The
PC/AT will respond to the asserted interrupt line by executing the
interrupt service routine corresponding to the interrupt line
asserted. The interrupt service routine is executed only if the IRQ
on the PC/AT’s 8259 interrupt controller has been previously
unmasked (see section 3 for programming details).
The interrupt service routine should respond to an interrupt by
accessing IP Interrupt Select (INTSEL*) space. The interrupt
service routine should also conclude the interrupt routine by
writing the “End-Of-Interrupt” command to the PC/AT’s 8259
interrupt controller (see section 3 for more details).
Power Failure Monitor
The carrier board contains a 5 volts undervoltage monitoring
circuit which provides a reset to the IP modules when the 5 volt
power drops below 4.27 volts typical / 4.15 volts minimum. This
circuitry is implemented per the Industrial I/O Pack specification.
Power Supply Fuses
The +5V, supply lines to each of the IP modules are
individually fused with a current limit of 2 amp imposed by the
fuses. In addition, the +12, and -12 supply lines to each of the
IP modules are individually fused with a current limit of 1 amp
imposed by the fuses. A blown fuse can be identified by visible
inspection or by use of an ohm meter. The fuses are located
under each IP slot near the “logic connectors” (see figure 4501-
671 or 4501-676).
Power Supply Filters
Power line filters are dedicated to each IP module for filtering
of the +5, +12, and -12 volt supplies. The power line filters are a
“T” type filter circuit comprising ferrite bead inductors and a feed-
through capacitor. The filters provide improved noise
performance as is required on precision analog IP modules.
5.0 SERVICE AND REPAIR
SERVICE AND REPAIR ASSISTANCE
Surface-Mounted Technology (SMT) boards are generally
difficult to repair. It is highly recommended that a non-functioning
board be returned to Acromag for repair. The board can be
damaged unless special SMT repair and service tools are used.
Further, Acromag has automated test equipment that thoroughly
checks the performance of each board. When a board is first
produced and when any repair is made, it is tested, placed in a
burn-in room at elevated temperature, and retested before
shipment.
Please refer to Acromag's Service Policy Bulletin or contact
Acromag for complete details on how to obtain parts and repair.
PRELIMINARY SERVICE PROCEDURE
Before beginning repair, be sure that all of the procedures in
Section 2, Preparation For Use, have been followed. Also, refer
to the documentation of your carrier board to verify that it is
correctly configured. Verify that there are no blown fuses.
Replacement of the carrier and/or IP with one that is known to
work correctly is a good technique to isolate a faulty board.
CAUTION: POWER MUST BE TURNED OFF BEFORE
REMOVING OR INSERTING BOARDS
Acromag’s Applications Engineers can provide further
technical assistance if required. When needed, complete repair
services are also available from Acromag.
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