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

1. 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。

2. 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。

3. 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：

1. D0 port Clower

   D0端口割草机

2. D1 port B

   D1端口B

3. D2 Mode

   D2模式

4. D3 port Cupper

   D3端口铜

5. D4 port A

   D4端口A

6. D5 Mode

   D5模式

7. D6 Mode

   D6模式

8. D7 BSR(Bit Set Reset)/I/O mode

   D7 BSR(位设置重置)/ I / O模式

We can set the CWL by using the IN and OUT command of the respective microprocessor.

我们可以使用相应微处理器的IN和OUT命令设置CWL。

翻译自: https://www.includehelp.com/embedded-system/the-8255-programmable-ic.aspx

可编程ic卡 通用吗