PCI-1751U User Manual
16
Chapter 3 Operation
3.1 Introduction
This chapter describes the operating characteristics of the PCI-1751U.
The driver software provided allows a user to access all of the card's func-
tions without register level programming. Please see the User's Manual
for the driver bundled with this card for more information. For users who
prefer to implement their own bit-level programming to drive the card's
functions, information useful for making such a program is included in
this chapter.
3.2 Digital I/O Ports
The PCI-1751U emulates two 8255 programmable peripheral interface
(PPI) chips in mode 0, but with higher driving capability than a standard
8255 chip. Each of the 8255 chips has 24 programmable I/O pins that are
divided into three 8-bit ports. The total 48 DI/O pins from both chips are
divided into 6 ports, designated PA0, PB0, PC0, PA1, PB1 and PC1.
Each port can be programmed as an input or an output port. The I/O pins
in port A0 are designated PA00, PA01,..., PA07; the pins in port B0 are
designated PB00, PB01,..., PB07, etc. These port names are used both in
this manual and in the software library. Refer to Section 2.5, Pin Assign-
ments.
3.2.1 8255 Mode 0
The basic functions of 8255 mode 0 include:
• Two 8-bit I/O ports - port A (PA) and port B (PB)
• Port C is divided into two nibble-wide (4-bit) I/O ports:- PC upper and
PC lower
• Any port can be used for either input or output.
• Output status can be read back.
Содержание PCI-1751U
Страница 1: ...PCI 1751U 48 bit Digital Input Output Card with Universal PCI Bus User Manual ...
Страница 5: ...2 CHAPTER 1 General Information ...
Страница 9: ...2 CHAPTER 2 Installation ...
Страница 15: ...11 Chapter2 2 5 PCI 1751U Block Diagram Figure 2 2 PCI 1751U Block Diagram ...
Страница 18: ...PCI 1751U User Manual 14 ...
Страница 19: ...2 CHAPTER 3 Operation ...
Страница 28: ...PCI 1751U User Manual 24 ...
Страница 29: ...2 APPENDIX A Function of 8254 Counter Chip ...
Страница 37: ...2 APPENDIX B Register Format of PCI 1751U ...