77 lines
2.3 KiB
C
77 lines
2.3 KiB
C
/*
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* @name: homework7.h
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* @author: msksbr
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* @date: 2025-05-24
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* @description: a header for homework7's homework tests
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* @version: 1.0f: fix errors in timer
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* variables:
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* 1.0:
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* 1. sbit DB_0 ~ sbit DB_7: pin number for led matrix cathodes
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* 2. pin number for 74HC138's address pins & enable pin
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* 2.1. sbit ADDR0 ~ sbit ADDR2: pin number for 74HC138's address pins
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* 2.2. sbit ADDR3 & sbit ENLED: pin number for 74HC138's enable pin
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* functions:
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* 1.0:
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* 1. void switch_138(unsigned char n): switch the 74HC138's address to n
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* 2. void delay_ms(unsigned char ms): a timer by ms base on timer0 mode 1
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*/
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#include <REG52.H>
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// variables:
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// 1. sbit DB_0 ~ sbit DB_7: pin number for led matrix cathodes
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sbit DB_0 = P2 ^ 0;
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sbit DB_1 = P2 ^ 1;
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sbit DB_2 = P2 ^ 2;
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sbit DB_3 = P2 ^ 3;
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sbit DB_4 = P2 ^ 4;
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sbit DB_5 = P2 ^ 5;
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sbit DB_6 = P2 ^ 6;
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sbit DB_7 = P2 ^ 7;
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// 2. pin number for 74HC138's address pins & enable pin
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// 2.1. sbit ADDR0 ~ sbit ADDR2: pin number for 74HC138's address pins
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sbit ADDR0 = P1 ^ 0; // @var ADDR0: to A(A0)
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sbit ADDR1 = P1 ^ 1; // @var ADDR1: to B(A1)
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sbit ADDR2 = P1 ^ 2; // @var ADDR2: to C(A2)
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// 2.2. sbit ADDR3 & sbit ENLED: pin number for 74HC138's enable pin
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sbit ADDR3 = P1 ^ 3; // @var ADDR3: to E2
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sbit ENLED = P1 ^ 4; // @var ENLED: to E3
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// functions:
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// 1. void switch_138(unsigned char n): switch the 74HC138's address to n
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void switch_138(unsigned char n)
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{
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bit A0, A1, A2;
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// @subsection: enable the 74HC138
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ENLED = 0;
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ADDR3 = 0;
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// @subsection: turn n to 3 bit binary number
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A0 = n & 0x01;
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A1 = (n >> 1) & 0x01;
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A2 = (n >> 2) & 0x01;
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// @subsection: switch the 74HC138's address to n
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ADDR0 = A0;
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ADDR1 = A1;
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ADDR2 = A2;
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}
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// 2. void delay_ms(unsigned char ms): a timer by ms base on timer0 mode 1
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void delay_ms(unsigned char ms)
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{
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TMOD &= 0xF0; // set the timer mode to 16-bit timer mode.
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TMOD |= 0x01; // set the timer mode to 16-bit timer mode.
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// 1ms timer definition:
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TH0 = 0XFC;
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TL0 = 0X18;
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// start the timer:
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TR0 = 1;
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while (ms--) {
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while (!TF0) {} // wait for the timer to overflow.
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TF0 = 0; // clear the timer flag.
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TH0 = 0XFC; // reload the timer value.
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TL0 = 0X18; // reload the timer value.
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}
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TR0 = 0; // stop the timer.
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} |