Chapter 4
Theory of Operation
4-2
©
National Instruments Corporation
•
Digital I/O circuitry
•
Calibration circuitry
The internal data and control buses interconnect the components. The rest
of this chapter explains the theory of operation of each of the PCI-1200
components. Calibration circuitry is discussed in Chapter 5,
PCI Interface Circuitry
The PCI-1200 interface circuitry consists of the MITE PCI interface chip
and a digital control logic chip. The MITE PCI interface chip provides a
mechanism for the PCI-1200 to communicate with the PCI bus. It is an
Application Specific Integrated Circuit (ASIC) designed by National
Instruments specifically for data acquisition. The digital control logic
chip connects the MITE PCI interface chip with the rest of the board.
The PCI-1200 is fully compliant with
PCI Local Bus Specification,
Revision 2.0
. Therefore, the base memory address and interrupt level for
the board are stored inside the MITE PCI interface chip at power on. You
do not need to set any switches or jumpers. The PCI bus is capable of 8-bit,
16-bit, or 32-bit transfers, but the PCI-1200 uses only 8-bit transfers.
Figure 4-2.
PCI Interface Circuitry
PCI Bus
Digital
Control
Logic
MITE
PCI
Interface
Chip
Data/Address
Interface Control
Error Reporting
Arbitration
System
Interrupt
1
2
2
2
6
37
Address
Data
Control
Interrupt
1
DRQ
1
Control/Data
4
8
5
