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:
1 #include <wiringPi.h> 2 #include <stdio.h> 3 #include <stdlib.h> 4 #include <stdint.h> 5 #include <time.h> 6 #define SCLK 12 7 #define RCLK 13 8 #define DIO 14 9 unsigned int code_char[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; 10 unsigned char code_segbit[]={0x01,0x02,0x04,0x08}; 11 int pins[3]={SCLK,RCLK,DIO}; 12 int init(){ 13 int i=0; 14 for(i=0;i<3;i++){ 15 pinMode(pins[i],OUTPUT); 16 digitalWrite(pins[i],LOW); 17 } 18 } 19 20 int destroy(){ 21 int i=0; 22 for(i=0;i<3;i++){ 23 digitalWrite(pins[i],LOW); 24 pinMode(pins[i],INPUT); 25 } 26 } 27 28 void loop(){ 29 time_t rawtime; 30 time(&rawtime); 31 struct tm *timeinfo; 32 timeinfo=localtime(&rawtime); 33 digitalWrite(RCLK,LOW); 34 if(timeinfo->tm_min>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_min%10]);//character 35 else shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_min]); 36 shiftOut(DIO,SCLK,1,code_segbit[0]);//bit 37 digitalWrite(RCLK,HIGH); 38 digitalWrite(RCLK,LOW); 39 if(timeinfo->tm_min>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_min/10]);//character 40 else shiftOut(DIO,SCLK,1,code_char[0]); 41 shiftOut(DIO,SCLK,1,code_segbit[1]);//bit 42 digitalWrite(RCLK,HIGH); 43 digitalWrite(RCLK,LOW); 44 if(timeinfo->tm_hour>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_hour%10]);//character 45 else shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_hour]); 46 shiftOut(DIO,SCLK,1,code_segbit[2]);//bit 47 digitalWrite(RCLK,HIGH); 48 digitalWrite(RCLK,LOW); 49 if(timeinfo->tm_hour>=10)shiftOut(DIO,SCLK,1,code_char[timeinfo->tm_hour/10]);//character 50 else shiftOut(DIO,SCLK,1,code_char[0]); 51 shiftOut(DIO,SCLK,1,code_segbit[3]);//bit 52 digitalWrite(RCLK,HIGH); 53 //printf("%d %d\t%d %d %d %d\n", 54 // timeinfo->tm_hour,timeinfo->tm_min, 55 // timeinfo->tm_hour/10,timeinfo->tm_hour%10, 56 // timeinfo->tm_min/10,timeinfo->tm_min%10); 57 delayMicroseconds(10); 58 } 59 60 int main(void){ 61 if(wiringPiSetup()==-1) //wiringPiSetupGpio==BCM 62 exit(1); 63 init(); 64 while(1) { 65 loop(); 66 } 67 destroy(); 68 return 0; 69 }
74HC595.h
1 /* 2 * wiringShift.h: 3 * Emulate some of the Arduino wiring functionality. 4 * 5 * Copyright (c) 2009-2012 Gordon Henderson. 6 *********************************************************************** 7 * This file is part of wiringPi: 8 * https://projects.drogon.net/raspberry-pi/wiringpi/ 9 * 10 * wiringPi is free software: you can redistribute it and/or modify 11 * it under the terms of the GNU Lesser General Public License as published by 12 * the Free Software Foundation, either version 3 of the License, or 13 * (at your option) any later version. 14 * 15 * wiringPi is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU Lesser General Public License for more details. 19 * 20 * You should have received a copy of the GNU Lesser General Public License 21 * along with wiringPi. If not, see <http://www.gnu.org/licenses/>. 22 *********************************************************************** 23 */ 24 25 #define LSBFIRST 0 26 #define MSBFIRST 1 27 28 #ifndef _STDINT_H 29 # include <stdint.h> 30 #endif 31 32 #ifdef __cplusplus 33 extern "C" { 34 #endif 35 36 extern uint8_t shiftIn (uint8_t dPin, uint8_t cPin, uint8_t order) ; 37 extern void shiftOut (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val) ; 38 39 #ifdef __cplusplus 40 } 41 #endif
74HC595.C
1 /* 2 * wiringShift.c: 3 * Emulate some of the Arduino wiring functionality. 4 * 5 * Copyright (c) 2009-2012 Gordon Henderson. 6 *********************************************************************** 7 * This file is part of wiringPi: 8 * https://projects.drogon.net/raspberry-pi/wiringpi/ 9 * 10 * wiringPi is free software: you can redistribute it and/or modify 11 * it under the terms of the GNU Lesser General Public License as published by 12 * the Free Software Foundation, either version 3 of the License, or 13 * (at your option) any later version. 14 * 15 * wiringPi is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU Lesser General Public License for more details. 19 * 20 * You should have received a copy of the GNU Lesser General Public License 21 * along with wiringPi. If not, see <http://www.gnu.org/licenses/>. 22 *********************************************************************** 23 */ 24 25 #include <stdint.h> 26 #include "wiringPi.h" 27 #include "wiringShift.h" 28 29 /* 30 * shiftIn: 31 * Shift data in from a clocked source 32 ********************************************************************************* 33 */ 34 35 uint8_t shiftIn (uint8_t dPin, uint8_t cPin, uint8_t order) 36 { 37 uint8_t value = 0 ; 38 int8_t i ; 39 40 if (order == MSBFIRST) 41 for (i = 7 ; i >= 0 ; --i) 42 { 43 digitalWrite (cPin, HIGH) ; 44 value |= digitalRead (dPin) << i ; 45 digitalWrite (cPin, LOW) ; 46 } 47 else 48 for (i = 0 ; i < 8 ; ++i) 49 { 50 digitalWrite (cPin, HIGH) ; 51 value |= digitalRead (dPin) << i ; 52 digitalWrite (cPin, LOW) ; 53 } 54 55 return value; 56 } 57 58 /* 59 * shiftOut: 60 * Shift data out to a clocked source 61 ********************************************************************************* 62 */ 63 void shiftOut (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val) 64 { 65 int8_t i; 66 if (order == MSBFIRST) 67 for (i = 7 ; i >= 0 ; --i) 68 { 69 digitalWrite (dPin, val & (1 << i)) ; 70 digitalWrite (cPin, HIGH) ; 71 digitalWrite (cPin, LOW) ; 72 } 73 else 74 for (i = 0 ; i < 8 ; ++i) 75 { 76 digitalWrite (dPin, val & (1 << i)) ; 77 digitalWrite (cPin, HIGH) ; 78 digitalWrite (cPin, LOW) ; 79 } 80 }
