可编程ic卡通用吗_8255可编程IC

可编程ic卡通用吗

Introduction

介绍

An 8255 programmable integrated circuit (IC) is an IC used for interfacing the microprocessor with the peripheral devices. It is a 40 pin IC which was introduced by INTEL to use with its 8085 and 8086 microprocessors.

8255可编程集成电路(IC)是用于将微处理器与外围设备接口的IC。它是INTEL推出的40引脚IC，用于其8085和8086微处理器。

Ports of 8255

端口8255

There are three input/output 8-bit ports in this IC namely port A, port B, port C. The port C can be divided into two each of 4 bits(C upper and C lower) according to requirement.

该IC中有3个输入/输出8位端口，即端口A，端口B，端口C。根据需要，端口C可以分为4位(C高和C低)中的两个。

Architecture of 8255

8255的体系结构

Pin diagram of 8255

8255的引脚图

The pins 1-4 and 37-40 are for Port A(PA0-PA7).
引脚1-4和37-40用于端口A(PA0-PA7)。
The pins 18-25 are for port B(PB0-PB7).
引脚18-25用于端口B(PB0-PB7)。
The pins 10-17 are for port C(PC0-PC7).
引脚10-17用于端口C(PC0-PC7)。
The pins 27-34 are for data bus(D0-D7) linked to the microprocessor.
引脚27-34用于链接到微处理器的数据总线(D0-D7)。
The RD(5) and WR(36) are two low active pins for reading and write operations respectively. When a low signal is sent to the pin no 5 it means a read operation is performing. Similarly, when a low signal is sent to pin no 36 this means the write operation is being performed.
RD(5)和WR(36)是两个低有效引脚，分别用于读取和写入操作。当低电平信号发送到5号引脚时，表示正在执行读操作。同样，当低信号发送到引脚36时，这意味着正在执行写操作。
The CS(chip select) is another low active pin that works as an enable to the IC.
CS(片选)是另一个低电平有效引脚，用作IC的使能。
The A0 and A1 are the control logic at 8 and 9.
A0和A1是8和9处的控制逻辑。
A0 A1
A0 A1
0 0 port A
0 0端口A
0 1 port B
0 1端口B
1 0 port C
1 0端口C
1 1 Control Word logic(CWR)
1 1控制字逻辑(CWR)
These select the ports.
这些选择端口。
The RESET pin at 35 used to reset the IC.
35处的RESET引脚用于复位IC。
The ground(7) and Vcc(26) are also present to establish the potential difference.
接地(7)和Vcc(26)也存在以建立电势差。

Modes of 8255

8255的模式

This IC works in 3 modes

该IC工作在3种模式

Mode 0 in which all the three ports act as input-output ports.
模式0，其中所有三个端口都充当输入-输出端口。
Mode 1 in which only port A and port B act as input-output port while port C is used for handshaking.
模式1，其中仅端口A和端口B充当输入-输出端口，而端口C用于握手。
Mode 2 in which only port A is used as a bidirectional port for both input-output.
模式2，其中仅端口A用作两个输入输出的双向端口。

Control word logic (CWL)

控制字逻辑(CWL)

Everything in the 8255 IC is dependent on the CWL. There are 8 bits in the CWL:

8255 IC中的所有内容均取决于CWL。 CWL中有8位：