可編程ic卡 通用嗎
Introduction
介紹
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可編程集成電路(IC)是用于將微處理器與外圍設備接口的IC。 它是INTEL推出的40引腳IC,用于其8085和8086微處理器。
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.
該IC中有3個輸入/輸出8位端口,即端口A,端口B,端口C。根據需要,端口C可以分為4位(C高和C低)中的兩個。
Architecture of 8255
8255的體系結構

Pin diagram of 8255
8255的引腳圖
The pins 1-4 and 37-40 are for Port A(PA0-PA7).
引腳1-4和37-40用于端口A(PA0-PA7)。
The pins 18-25 are for port B(PB0-PB7).
引腳18-25用于端口B(PB0-PB7)。
The pins 10-17 are for port C(PC0-PC7).
引腳10-17用于端口C(PC0-PC7)。
The pins 27-34 are for data bus(D0-D7) linked to the microprocessor.
引腳27-34用于鏈接到微處理器的數據總線(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)是兩個低有效引腳,分別用于讀取和寫入操作。 當低電平信號發送到5號引腳時,表示正在執行讀操作。 同樣,當低信號發送到引腳36時,這意味著正在執行寫操作。
The CS(chip select) is another low active pin that works as an enable to the IC.
CS(片選)是另一個低電平有效引腳,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處的控制邏輯。
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控制字邏輯(CWR)
These select the ports.
這些選擇端口。
The RESET pin at 35 used to reset the IC.
35處的RESET引腳用于復位IC。
The ground(7) and Vcc(26) are also present to establish the potential difference.
接地(7)和Vcc(26)也存在以建立電勢差。
Modes of 8255
8255的模式
This IC works in 3 modes
該IC工作在3種模式
Mode 0 in which all the three ports act as input-output ports.
模式0,其中所有三個端口都充當輸入-輸出端口。
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,其中僅端口A和端口B充當輸入-輸出端口,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,其中僅端口A用作兩個輸入輸出的雙向端口。
Control word logic (CWL)
控制字邏輯(CWL)
Everything in the 8255 IC is dependent on the CWL. There are 8 bits in the CWL:
8255 IC中的所有內容均取決于CWL。 CWL中有8位:

D0 port Clower
D0端口割草機
D1 port B
D1端口B
D2 Mode
D2模式
D3 port Cupper
D3端口銅
D4 port A
D4端口A
D5 Mode
D5模式
D6 Mode
D6模式
D7 BSR(Bit Set Reset)/I/O mode
D7 BSR(位設置重置)/ I / O模式
We can set the CWL by using the IN and OUT command of the respective microprocessor.
我們可以使用相應微處理器的IN和OUT命令設置CWL。
翻譯自: https://www.includehelp.com/embedded-system/the-8255-programmable-ic.aspx
可編程ic卡 通用嗎