Note20241017 This page is being updated - work in progress…

This course is Microcontroller, offered by the Faculty of Electronics Engineering & Technology.

[20241017] Updating this for 202425s1 Academic Session.

• Lecture 1 - Overview
• Lecture 2 - Architecture
• Lecture 3 - C for 8051
• Lecture 4 - 8051 I/O
• Lecture 5 - 8051 Timer
• Lecture 6 - 8051 Serial Interface
• Lecture 7 - 8051 Interrupt
• Lecture 8 - 8051 System Management

Introduction to using 'library' code. Single header include file(s) meant for single source compilation. These are meant to be compiled using Keil 8051 compiler.

I recommend to use my include file (mcu51.h) rather than the regular (reg51.h) because it would be easier for you to use my example codes and library. I wrote and tested them using my own syntax that can be used on both Keil and SDCC compilers. Simply extract this zip file and setup the include path. Ask me during lab session if you do not know how to do that.

uart.h

#ifndef __MY1UART_H__
#define __MY1UART_H__
 
/* note: this is NOT compatible with keil's printf */
void uart_init(void) {
	SCON = 0x50;
	TMOD &= 0x0F;
	TMOD |= 0x20;
	TH1 = 253;
	TR1 = 1;
}
 
void uart_send(unsigned char sdat) {
	SBUF = sdat;
	while (TI==0);
	TI = 0;
}
 
unsigned char uart_read(void) {
	unsigned char rdat;
	while (RI==0);
	rdat = SBUF;
	RI = 0;
	return rdat;
}
 
void uart_puts(char* text) {
	while (*text) {
		uart_send(*text);
		text++;
	}
}
 
#endif /* __MY1UART_H__ */

tlcd.h

#ifndef __MY1TLCD_H__
#define __MY1TLCD_H__
 
#define LCD_DATA P2
sbit LCD_RS = P0^7;
sbit LCD_RW = P0^6;
sbit LCD_EN = P0^5;
 
void tlcd_delay(unsigned char step) {
	unsigned int loop;
	do {
		loop = 1000; while (--loop);
	} while (--step);
}
 
void tlcd_write(unsigned char cdat) {
	LCD_RS = 1;
	LCD_RW = 0;
	LCD_DATA = cdat;
	LCD_EN = 1;
	LCD_EN = 0;
	tlcd_delay(1);
}
 
void tlcd_cmd(unsigned char ccmd) {
	LCD_RS = 0;
	LCD_RW = 0;
	LCD_DATA = ccmd;
	LCD_EN = 1;
	LCD_EN = 0;
	tlcd_delay(2);
}
 
void tlcd_init(void) {
	tlcd_cmd(0x38); /* 8 bit mode, 1/16 duty, 5x8 font */
	tlcd_cmd(0x38);
	tlcd_cmd(0x38);
	tlcd_cmd(0x06); /* display off */
	tlcd_cmd(0x0c); /* display on, blink cursor on */
	tlcd_cmd(0x01); /* clear display */
}
 
void tlcd_puts(char* text) {
	while (*text) {
		tlcd_write(*text);
		text++;
	}
}
 
#endif /* __MY1TLCD_H__ */

timer.h

#ifndef __MY1TIMER_H__
#define __MY1TIMER_H__
 
// useful macro!
#define timer0_init() { TMOD &= 0xF0; TMOD |= 0x01; }
#define timer0_prep(hi,lo) { TH0 = hi; TL0 = lo; }
#define timer0_stop() { TR0 = 0; TF0 = 0; }
#define timer0_exec() { TR0 = 1; }
#define timer0_flag() { timer0_exec(); while (!TF0); }
#define timer0_wait(hi,lo) { timer0_prep(hi,lo); timer0_flag(); timer0_stop(); }
#define timer0_null() { TH0 = 0; TL0 = 0; }
#define timer0_read() ((unsigned int)TH0<<8)|TL0
 
void timer0_delayms(unsigned int step) {
	do {
		timer0_wait(0xfc,0x66); // 1 ms delay
	} while (--step);
}
 
#endif /* __MY1TIMER_H__ */

utils.h

#ifndef __MY1UTILS_H__
#define __MY1UTILS_H__
 
unsigned char uint8_2cstr(char* cstr, unsigned char that) {
	unsigned char size, temp;
	size = 0;
	temp = that/100;
	if (temp) {
		that %= 100;
		cstr[size++] = temp + 0x30;
	}
	temp = that/10;
	if (temp) {
		that %= 10;
		cstr[size++] = temp + 0x30;
	} else if (size)
		cstr[size++] = 0x30;
	cstr[size++] = that + 0x30;
	cstr[size] = 0x0;
	return size;
}
 
unsigned char int8_2cstr(char* cstr, signed char that) {
	if (that<0) {
		that = -that;
		*cstr = '-';
		cstr++;
	}
	return uint8_2cstr(cstr,(unsigned char)that);
}
 
unsigned char uint16_2cstr(char* cstr, unsigned int that) {
	unsigned char size, temp;
	unsigned int idiv;
	size = 0; idiv = 10000;
	while (idiv>=10) {
		temp = (unsigned char)(that/idiv);
		if (temp) {
			that %= idiv;
			cstr[size++] = temp + 0x30;
		} else if (size)
			cstr[size++] = 0x30;
		idiv /= 10;
	}
	cstr[size++] = that + 0x30;
	cstr[size] = 0x0;
	return size;
}
 
unsigned char int16_2cstr(char* cstr, int that) {
	if (that<0) {
		that = -that;
		*cstr = '-';
		cstr++;
	}
	return uint16_2cstr(cstr,(unsigned int)that);
}
 
unsigned char cstr_2uint8(char* pstr, unsigned char* pval) {
	unsigned char loop;
	*pval = 0; loop = 0;
	while (pstr[loop]) {
		if (pstr[loop]<0x30||pstr[loop]>0x39) {
			loop = 0;
			break;
		}
		*pval = (*pval*10) + (pstr[loop]-0x30);
		loop++;
	}
	return loop;
}
 
unsigned char cstr_2uint16(char* pstr, unsigned int* pval) {
	unsigned char loop;
	*pval = 0; loop = 0;
	while (pstr[loop]) {
		if (pstr[loop]<0x30||pstr[loop]>0x39) {
			loop = 0;
			break;
		}
		*pval = (*pval*10) + (pstr[loop]-0x30);
		loop++;
	}
	return loop;
}
 
unsigned char cstr_2int16(char* pstr, int* pval) {
	unsigned char loop, skip;
	skip = (pstr[0]=='-') ? 1 : 0;
	loop = cstr_2uint16(&pstr[skip],(unsigned int*)pval);
	if (skip) *pval = -(*pval);
	return loop;
}
 
#endif /** __MY1UTILS_H__ */

kpad.h

#ifndef __MY1KPAD_H__
#define __MY1KPAD_H__
 
/* 4x4 keypad interface {R0,R1,R2,R3,C0,C1,C2,C3} */
/* 4x3 keypad interface {C1,R0,C0,R3,C2,R2,R1} */
 
/** DefaultPins: C0-C3 => P1.4-P1.7, R0-R3 => P1.0-P1.3 */
#ifndef KEY_DATA
#define KEY_DATA P1
#endif
#ifndef _ROWS_AT_UPPER_
#define ROWS_FLAG 0x01
#define COLS_FLAG 0x10
#else
#define ROWS_FLAG 0x10
#define COLS_FLAG 0x01
#endif
 
/** no-key indicator for keypad */
#define KEY_NOT_CODE 0x10
 
unsigned char key_scan(void) {
	/** scan for key press */
	unsigned char irow, icol, mask, test;
	mask = ROWS_FLAG;
	for (irow=0;irow<4;irow++) {
		KEY_DATA = ~mask; test = COLS_FLAG;
		for (icol=0;icol<4;icol++) {
			if ((KEY_DATA&test)==0) {
				while ((KEY_DATA&test)==0);
				if (icol==3) return irow+0x0A;
				if (irow==0) return icol+1;
				if (irow==1) return icol+4;
				if (irow==2) return icol+7;
				if (icol==1) return 0;
				return (icol>>1)+0x0e;
			}
			test <<= 1;
		}
		mask <<= 1;
	}
	return KEY_NOT_CODE;
}
 
unsigned char key_wait(void) {
	/** wait for key press */
	unsigned char scan;
	while ((scan=key_scan())==KEY_NOT_CODE);
	return scan;
}