From 3ac92b944264b434cebb6b861de62580d0e1dc1a Mon Sep 17 00:00:00 2001
From: Suhayl <838119509@qq.com>
Date: Mon, 16 Jul 2018 09:01:47 +0800
Subject: [PATCH] Update the C code of the 4-digital-display

After the system is updated, in the ShiftOut function, the IO port pin
changes too fast, resulting in communication abnormality with 74HC595.
In the update, the SHIFT function is override.
---
 Code/C_Code/18.2.1_StopWatch/StopWatch.c | 40 +++++++++++++++++++-----
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/Code/C_Code/18.2.1_StopWatch/StopWatch.c b/Code/C_Code/18.2.1_StopWatch/StopWatch.c
index 765e7de..05ae9f5 100644
--- a/Code/C_Code/18.2.1_StopWatch/StopWatch.c
+++ b/Code/C_Code/18.2.1_StopWatch/StopWatch.c
@@ -2,7 +2,7 @@
 * Filename    : StopWatch.c
 * Description : Control 4_Digit_7_Segment_Display by 74HC595
 * Author      : freenove
-* modification: 2016/07/07
+* modification: 2018/07/16
 **********************************************************************/
 #include <wiringPi.h>
 #include <stdio.h>
@@ -23,24 +23,48 @@ void selectDigit(int digit){
     digitalWrite(digitPin[2],((digit&0x02) == 0x02) ? LOW : HIGH);
     digitalWrite(digitPin[3],((digit&0x01) == 0x01) ? LOW : HIGH);
 }
-void outData(int8_t data){      //function used to output data for 74HC595输出数据函数
+void _shiftOut(int dPin,int cPin,int order,int val){   
+	int i;  
+    for(i = 0; i < 8; i++){
+        digitalWrite(cPin,LOW);
+        if(order == LSBFIRST){
+            digitalWrite(dPin,((0x01&(val>>i)) == 0x01) ? HIGH : LOW);
+            delayMicroseconds(1);
+		}
+        else {//if(order == MSBFIRST){
+            digitalWrite(dPin,((0x80&(val<<i)) == 0x80) ? HIGH : LOW);
+            delayMicroseconds(1);
+		}
+        digitalWrite(cPin,HIGH);
+        delayMicroseconds(1);
+	}
+}
+void outData(int8_t data){      //function used to output data for 74HC595
     digitalWrite(latchPin,LOW);
-    shiftOut(dataPin,clockPin,MSBFIRST,data);
+    _shiftOut(dataPin,clockPin,MSBFIRST,data);
     digitalWrite(latchPin,HIGH);
 }
 void display(int dec){  //display function for 7-segment display
+	int delays = 1;
+	outData(0xff);	
     selectDigit(0x01);      //select the first, and display the single digit
     outData(num[dec%10]);   
-    delay(1);               //display duration
+    delay(delays);               //display duration
+    
+    outData(0xff);    
     selectDigit(0x02);      //select the second, and display the tens digit
     outData(num[dec%100/10]);
-    delay(1);
+    delay(delays);
+    
+    outData(0xff);    
     selectDigit(0x04);      //select the third, and display the hundreds digit
     outData(num[dec%1000/100]);
-    delay(1);
+    delay(delays);
+    
+    outData(0xff);    
     selectDigit(0x08);      //select the fourth, and display the thousands digit
     outData(num[dec%10000/1000]);
-    delay(1);
+    delay(delays);
 }
 void timer(int  sig){       //Timer function
     if(sig == SIGALRM){   //If the signal is SIGALRM, the value of counter plus 1, and update the number displayed by 7-segment display
@@ -62,7 +86,7 @@ int main(void)
     //set the pin connected to 7-segment display common end to output mode
     for(i=0;i<4;i++){       
         pinMode(digitPin[i],OUTPUT);
-        digitalWrite(digitPin[i],LOW);
+        digitalWrite(digitPin[i],HIGH);
     }
     signal(SIGALRM,timer);  //configure the timer
     alarm(1);               //set the time of timer to 1s