archieve: homework5

homework5/src/test1.c

@@ -5,17 +5,20 @@
 #include "homework5.h"
 unsigned char LedBuff[6] = {
     0xFF, 0XFF, 0XFF, 0XFF, 0XFF, 0XFF};
-unsigned char i = 0;
+unsigned char i             = 0;
+unsigned char display_id[6] = {1, 3, 0, 0, 7, 1};
 
 void test1()
 {
     // display the number on the Seg.
-    LedBuff[5] = LedChar[1];
-    LedBuff[4] = LedChar[3];
-    LedBuff[3] = LedChar[0];
-    LedBuff[2] = LedChar[0];
-    LedBuff[1] = LedChar[7];
-    LedBuff[0] = LedChar[1];
+    // 5 is high digit.
+    // 0 is low digit.
+    LedBuff[5] = LedChar[display_id[0]];
+    LedBuff[4] = LedChar[display_id[1]];
+    LedBuff[3] = LedChar[display_id[2]];
+    LedBuff[2] = LedChar[display_id[3]];
+    LedBuff[1] = LedChar[display_id[4]];
+    LedBuff[0] = LedChar[display_id[5]];
     while (1) {
         /*
          * seg id on 38 transistors:

homework5/src/test2.c

@@ -69,6 +69,8 @@ void test2()
                 }
             }
             // log the number in the buffer.
+            // 5 is high digit.
+            // 0 is low digit.
             LedBuff[5] = LedChar[hour / 10];   // log the hour tens.
             LedBuff[4] = LedChar[hour % 10];   // log the hour units.
             LedBuff[3] = LedChar[minute / 10]; // log the minute tens.

homework5/src/test3.c

@@ -13,10 +13,9 @@
  * 7. msksbr NB!!!
  * 8. msksbr NB!!!
  */
-*/
 
 #include "homework5.h"
-    unsigned char LedBuff[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}; // buffer to store the seg chars.
+unsigned char LedBuff[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}; // buffer to store the seg chars.
 
 void test3()
 {
@@ -67,6 +66,8 @@ void test3()
             }
             // log the number in the buffer.
             // only log the valid digits.
+            // 5 is high digit.
+            // 0 is low digit.
             LedBuff[5] = hour >= 10 ? LedChar[hour / 10] : 0XFF;                     // log the hour tens.
             LedBuff[4] = hour > 0 ? LedChar[hour % 10] : 0XFF;                       // log the hour units.
             LedBuff[3] = (minute >= 10 || hour > 0) ? LedChar[minute / 10] : 0XFF;   // log the minute tens.

homework5/src/test4.c

@@ -0,0 +1,70 @@
+// test4.c
+// 写一个从999999开始倒计时的秒表。并且改用定时器T1的中断来完成
+// make a stopwatch that counts down from 999999. and use interrupt to finish it.
+
+#include "homework5.h"
+unsigned char LedBuff[6]            = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}; // buffer to store the seg chars.
+volatile unsigned char i            = 0;                                    // to current digit.
+volatile unsigned long display_time = 999999;                               // to store the time to display.
+unsigned int cnt                    = 0;                                    // to count interrupt.
+
+// init timer
+void initTimer(void)
+{
+    TMOD &= 0x0F; // clear TMOD.
+    TMOD |= 0x10; // set TMOD to mode 1.
+    TH1 = 0xFC;   // 1ms timer.
+    TL1 = 0x18;
+    ET1 = 1; // enable timer 1 interrupt.
+    EA  = 1; // enable global interrupt.
+    TR1 = 1; // start timer 1.
+}
+
+// timer1 interrupt service routine.
+void timer1ISR(void) interrupt 3
+{
+    TH1 = 0xFC; // reset timer.
+    TL1 = 0x18;
+
+    // display the number.
+    set38Transistors(i);
+    P2 = LedBuff[i];
+    i  = (i + 1) % 6; // to switch to the next digit.
+
+    // 1s timer.
+    if (++cnt >= 1000) { // if reached 1s.
+        cnt = 0;
+        if (display_time > 0) {
+            display_time--; // decrease the time.
+        }
+    }
+}
+
+void test4()
+{
+    initTimer();
+    while (1) {
+        // split the time into 6 digits.
+        unsigned char first_digit  = display_time / 100000;           // to get the first digit.
+        unsigned char second_digit = (display_time % 100000) / 10000; // to get the second digit.
+        unsigned char third_digit  = (display_time % 10000) / 1000;   // to get the third digit.
+        unsigned char fourth_digit = (display_time % 1000) / 100;     // to get the fourth digit.
+        unsigned char fifth_digit  = (display_time % 100) / 10;       // to get the fifth digit.
+        unsigned char sixth_digit  = display_time % 10;               // to get the sixth digit.
+
+        // load the number in the buffer.
+        // 5 is high digit.
+        // 0 is low digit.
+        LedBuff[5] = LedChar[first_digit];  // to display the first digit.
+        LedBuff[4] = LedChar[second_digit]; // to display the second digit.
+        LedBuff[3] = LedChar[third_digit];  // to display the third digit.
+        LedBuff[2] = LedChar[fourth_digit]; // to display the fourth digit.
+        LedBuff[1] = LedChar[fifth_digit];  // to display the fifth digit.
+        LedBuff[0] = LedChar[sixth_digit];  // to display the sixth digit.
+    }
+}
+
+void main()
+{
+    test4();
+}