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[]={SCLK,RCLK,DIO};
 int init(){
     int i=;
     for(i=;i<;i++){
     pinMode(pins[i],OUTPUT);
     digitalWrite(pins[i],LOW);
     }
 }

 int destroy(){
     int i=;
     for(i=;i<;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>=)shiftOut(DIO,SCLK,,code_char[timeinfo->tm_min%]);//character
     else shiftOut(DIO,SCLK,,code_char[timeinfo->tm_min]);
     shiftOut(DIO,SCLK,,code_segbit[]);//bit
     digitalWrite(RCLK,HIGH);
     digitalWrite(RCLK,LOW);
     if(timeinfo->tm_min>=)shiftOut(DIO,SCLK,,code_char[timeinfo->tm_min/]);//character
     else shiftOut(DIO,SCLK,,code_char[]);
     shiftOut(DIO,SCLK,,code_segbit[]);//bit
     digitalWrite(RCLK,HIGH);
     digitalWrite(RCLK,LOW);
     if(timeinfo->tm_hour>=)shiftOut(DIO,SCLK,,code_char[timeinfo->tm_hour%]);//character
     else shiftOut(DIO,SCLK,,code_char[timeinfo->tm_hour]);
     shiftOut(DIO,SCLK,,code_segbit[]);//bit
     digitalWrite(RCLK,HIGH);
     digitalWrite(RCLK,LOW);
     if(timeinfo->tm_hour>=)shiftOut(DIO,SCLK,,code_char[timeinfo->tm_hour/]);//character
     else shiftOut(DIO,SCLK,,code_char[]);
     shiftOut(DIO,SCLK,,code_segbit[]);//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();
 }

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

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 =  ;
   int8_t  i ;

   if (order == MSBFIRST)
     for (i =  ; i >=  ; --i)
     {
       digitalWrite (cPin, HIGH) ;
       value |= digitalRead (dPin) << i ;
       digitalWrite (cPin, LOW) ;
     }
   else
     for (i =  ; i <  ; ++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 =  ; i >=  ; --i)
     {
       digitalWrite (dPin, val & ( << i)) ;
       digitalWrite (cPin, HIGH) ;
       digitalWrite (cPin, LOW) ;
     }
   else
     for (i =  ; i <  ; ++i)
     {
       digitalWrite (dPin, val & ( << i)) ;
       digitalWrite (cPin, HIGH) ;
       digitalWrite (cPin, LOW) ;
     }
 }