树莓派进阶之路 (016) - 通过595驱动4位LED显示系统时间

模块图片,4位共阳极数码管.

我们使用树莓派wiringPi的库来通过74HC595驱动4位数码管:

C 代码如下: 

#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <time.h>
#define SCLK 12
#define RCLK 13
#define DIO 14
unsigned int code_char[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};
unsigned char code_segbit[]={0x01,0x02,0x04,0x08};
int pins[3]={SCLK,RCLK,DIO};
int init(){
    int i=0;
    for(i=0;i<3;i++){
    pinMode(pins[i],OUTPUT);
    digitalWrite(pins[i],LOW);
    }
}

int destroy(){
    int i=0;
    for(i=0;i<3;i++){
    digitalWrite(pins[i],LOW);
    pinMode(pins[i],INPUT);
    }
}

void loop(){
    time_t rawtime;
    time(&rawtime);
    struct tm *timeinfo;
    timeinfo=localtime(&rawtime);
    digitalWrite(RCLK,LOW);
    if(timeinfo->tm_min>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_min%10]);//character
    else shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_min]);
    shiftOut(DIO,SCLK,1,code_segbit[0]);//bit
    digitalWrite(RCLK,HIGH);
    digitalWrite(RCLK,LOW);
    if(timeinfo->tm_min>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_min/10]);//character
    else shiftOut(DIO,SCLK,1,code_char[0]);
    shiftOut(DIO,SCLK,1,code_segbit[1]);//bit
    digitalWrite(RCLK,HIGH);
    digitalWrite(RCLK,LOW);
    if(timeinfo->tm_hour>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_hour%10]);//character
    else shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_hour]);
    shiftOut(DIO,SCLK,1,code_segbit[2]);//bit
    digitalWrite(RCLK,HIGH);
    digitalWrite(RCLK,LOW);
    if(timeinfo->tm_hour>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_hour/10]);//character
    else shiftOut(DIO,SCLK,1,code_char[0]);
    shiftOut(DIO,SCLK,1,code_segbit[3]);//bit
    digitalWrite(RCLK,HIGH);
    //printf("%d %d\t%d %d %d %d\n",
    // timeinfo->tm_hour,timeinfo->tm_min,
    // timeinfo->tm_hour/10,timeinfo->tm_hour%10,
    // timeinfo->tm_min/10,timeinfo->tm_min%10);
    delayMicroseconds(10);
}

int main(void){
    if(wiringPiSetup()==-1) //wiringPiSetupGpio==BCM
        exit(1);
    init();
    while(1) {
        loop();
    }
    destroy();
    return 0;
}

 

74HC595.h

/*
 * wiringShift.h:
 *    Emulate some of the Arduino wiring functionality. 
 *
 * Copyright (c) 2009-2012 Gordon Henderson.
 ***********************************************************************
 * This file is part of wiringPi:
 *    https://projects.drogon.net/raspberry-pi/wiringpi/
 *
 *    wiringPi is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    wiringPi is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with wiringPi.  If not, see <http://www.gnu.org/licenses/>.
 ***********************************************************************
 */

#define    LSBFIRST    0
#define    MSBFIRST    1

#ifndef    _STDINT_H
# include <stdint.h>
#endif

#ifdef __cplusplus
extern "C" {
#endif

extern uint8_t shiftIn      (uint8_t dPin, uint8_t cPin, uint8_t order) ;
extern void    shiftOut     (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val) ;

#ifdef __cplusplus
}
#endif

 

74HC595.C

/*
 * wiringShift.c:
 *    Emulate some of the Arduino wiring functionality. 
 *
 * Copyright (c) 2009-2012 Gordon Henderson.
 ***********************************************************************
 * This file is part of wiringPi:
 *    https://projects.drogon.net/raspberry-pi/wiringpi/
 *
 *    wiringPi is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    wiringPi is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with wiringPi.  If not, see <http://www.gnu.org/licenses/>.
 ***********************************************************************
 */

#include <stdint.h>
#include "wiringPi.h"
#include "wiringShift.h"

/*
 * shiftIn:
 *    Shift data in from a clocked source
 *********************************************************************************
 */

uint8_t shiftIn (uint8_t dPin, uint8_t cPin, uint8_t order)
{
  uint8_t value = 0 ;
  int8_t  i ;
 
  if (order == MSBFIRST)
    for (i = 7 ; i >= 0 ; --i)
    {
      digitalWrite (cPin, HIGH) ;
      value |= digitalRead (dPin) << i ;
      digitalWrite (cPin, LOW) ;
    }
  else
    for (i = 0 ; i < 8 ; ++i)
    {
      digitalWrite (cPin, HIGH) ;
      value |= digitalRead (dPin) << i ;
      digitalWrite (cPin, LOW) ;
    }

  return value;
}

/*
 * shiftOut:
 *    Shift data out to a clocked source
 *********************************************************************************
 */
void shiftOut (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val)
{
  int8_t i;
  if (order == MSBFIRST)
    for (i = 7 ; i >= 0 ; --i)
    {
      digitalWrite (dPin, val & (1 << i)) ;
      digitalWrite (cPin, HIGH) ;
      digitalWrite (cPin, LOW) ;
    }
  else
    for (i = 0 ; i < 8 ; ++i)
    {
      digitalWrite (dPin, val & (1 << i)) ;
      digitalWrite (cPin, HIGH) ;
      digitalWrite (cPin, LOW) ;
    }
}