用AtmelStudio6.2跑mega16例程（57)8255扩展

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楼主 | 2014-11-21 21:48 | 只看该作者 |只看大图回帖奖励

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Atmelstudio, mega16, buffer, ISP, ui

本例通过8255接口扩展芯片控制8只集成式七段数码管。PC口增加3个按键。
8255的3个I/O端口和一个命令端口的定义。由于8255的接口地址仅需要单片机地址端口的高8位控制，这8位地十中实际仅使用的低3位,它们分别对应CS、A1、A0，其中A1与A0地址线可选择8255的4个端口地址之一。

Atmel Studio6.2的截图：

程序清单：

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/*

* GccApplication20.c

*

* Created: 2014-11-21 21:19:28

* Author: Administrator

*/ 



/*

* GccApplication1.c

*

* Created: 2014-11-21 6:15:19

* Author: Administrator

*/ 



#define F_CPU 2000000UL

#include <avr/io.h>

#include <avr/interrupt.h>

#include <util/delay.h>

#include <stdint.h>



#define PA (uint8_t*)0xFF00

#define PB (uint8_t*)0xFF01

#define PC (uint8_t*)0xFF02

#define COM (uint8_t*)0xFF03



const uint8_t SEG_CODE[] = {0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0xbf};



uint8_t Disp_Buffer[] = {1,2,10,3,0,5,0};



uint8_t Pre_Key_State = 0x00;



void Key_Process()

{

uint8_t Key_State,t;

Key_State = *PC;

if(Key_State==Pre_Key_State)return;

Pre_Key_State = Key_State;

switch(Key_State)

{

case(uint8_t)~_BV(0):

t = Disp_Buffer[0] * 10 + Disp_Buffer[1];

if(++t == 24) t = 0;

Disp_Buffer[0] = t/10;

Disp_Buffer[1] = t%10;

break;

case (uint8_t)~_BV(2):

t = Disp_Buffer[3] * 10 + Disp_Buffer[4];

if(++t == 60) t = 1;

Disp_Buffer[3] = t /10;

Disp_Buffer[4] = t % 10;

break;

case (uint8_t)~_BV(4):

t = Disp_Buffer[6] * 10 + Disp_Buffer[7];

if( ++t == 60) t=1;

Disp_Buffer[6] = t /10;

Disp_Buffer[7] = t %10;

break;

default:

break;



}

}









int main(void)

{

uint8_t i;

MCUCR |= 0x80;

* COM = 0B10001001; //8255工作方式选择





while(1)

{

for(i=0;i<8;i++)

{

*PB = _BV(i);

*PA = (uint8_t)SEG_CODE[Disp_Buffer[i]];

_delay_ms(2);

Key_Process();

}

//TODO:: Please write your application code 

}

}