霍尔磁测速-自行车测距仪-MC68HC908QY4-1601LCD显示-C语言程序-电路图-转载自国外网站 - 圣源电子制作

/*
lcd.c firmware for Distant Meter V1.0
the sensor is simple reed switch with magnet tied
to bycycle wheel. Optional 8-bit analog display for
user sensor.
MC908QY4CP 16-pin MCU
compiled with icc08
Copyright (c) 2004 Wichit Sirichote
*/
#include <io908QY4.H>
#define one_revolution 157 // 2PIr, radius is 25cm
#define p 1 // scale of ADC reading
char temp,k;
unsigned int PV,temp16;
char i,n,timer1,timer2;
unsigned char sec;
char x1,x2,x3;
long average,length, count;
char diff,old, now;
char *title = "DISTANCE METER 1";
char buffer[10];
/* signal for lcd interface
E PTB1
RS PTB0
D4 PTB4
D5 PTB5
D6 PTB6
D7 PTB7
D0-D3 and R/W# are tied to GND
*/
void delay(int j)
{
unsigned int i;
for (i = 0; i < j; i++)
COPCTL = 0; // clear COP otherwise the cpu itself will be reset
}
void pulseE()
{
PTB |= 2;
delay(10);
PTB &= ~2;
}
void LCDWI(char c) /* write instruction to instruction register */
{
temp = c;
PTB &= ~3; // clear RS and E
PTB &= 0x0f; // clear high nibbel to low
c &= 0xf0; // prepare only high nibble
PTB |= c;
pulseE();
c = temp;
c <<=4;
PTB &= 0x0f;
PTB |= c;
pulseE();
delay(50);
}
void
LCDWD(char c) /* write data to data register */
{
temp = c;
PTB |= 1; // set bit RS
PTB &= ~2; // clear bit E
PTB &= 0x0f; // clear high nibbel to low
c &= 0xf0; // prepare only high nibble
PTB |= c; // mearge high nibble first
pulseE();
c = temp;
c <<=4;
PTB &= 0x0f;
PTB |= c;
pulseE();
delay(50);
}
void i_LCD() /* initialize LCD in accordance with Hitachi 44780 4-bit
mode */
{
PTB &= ~3; // clear RS and E
PTB |= 0x30;
pulseE();
delay(200);
pulseE();
delay(50);
pulseE();
delay(50);
PTB &= 0x0f;
PTB |= 0x20;
pulseE();
pulseE();
pulseE();
LCDWI(0x28); // set 4-bit bus, 1/16 line, 5*7 dots
LCDWI(0x0c); // display on/off on display,off cursor, no blink
LCDWI(0x06); // entry mode DDRAM auto address increment
LCDWI(1); // clear display
delay(50);
}
// print LCD text >8
// the 16x1 line LCD has two blocks start address!
void print_lcds(char *s)
{
char i;
LCDWI(1); // clear display
LCDWI(0x80); // start at left most position
for(i=0; i<8; i++)
LCDWD(*s++);
LCDWI(0xc0); // new address for position 9
for(i=0; i<8; i++)
LCDWD(*s++);
}
char read_ADC()
{
ADSCR = 0; // read channel 0 one time
while(!(ADSCR&0x80))
;
return ADR;
}
// 3-point moving average (digital filtering)
long read_ADC_filter(){
PV = read_ADC();
x3 = x2;
x2 = x1;
x1 = PV;
PV = (x1+x2+x3)/3;
return PV;
}
int read_adc_scale(){
long k;
k = read_ADC_filter()*p;
return k;
}
void print_dec(char d,unsigned int n)
{
buffer[0] = n/10000+48;
temp16 = n%10000;
buffer[1] = temp16/1000+48;
temp16 %=1000;
buffer[2] = temp16/100+48;
temp16 %=100;
buffer[3] = temp16/10+48;
buffer[4] = temp16%10+48;
LCDWI(d);
for(i=0; i<5; i++)
LCDWD(buffer[i]);
}
void print_distant()
{
if(++timer1>10)
{
timer1 = 0;
PTA ^= 2; // toggle PA1
// count++; // test auto increment
length = count*one_revolution; // one revolution = 157cm
print_dec(0x80,length/100); // 100cm = 1m
LCDWD(' ');
LCDWD('m');
print_dec(0xc0,read_adc_scale());
}
}
void task_led()
{
if(++timer2>50)
{
timer2 =0;
LCDWI(0xc7);
k^=1;
if (k) LCDWD('-');
else LCDWD('_');
}
}
// PTA2 input bit for reed swicth sensor
// detect rising edge
void detect_pulse_input()
{
now = PTA&4; // read only PTA2
diff = old-now;
if(diff>4) count++;
old = now;
}
void print_average()
{
average += count;
average /= 2;
print_dec(0xc0,average);
}
void main()
{
// OCSTRIM = 0x81; // trim internal oscillator
delay(1000); // powerup delay for LCD
n = k=0;
count = 0;
average = 0;
TMODH = 0x01;
TMODL = 0xf4;
TSC = 0x06; // run timer
DDRA = ~0x1; // PA0 is ADC input
DDRB = 0xff; // port B is output port
PTB = 0; // clear port B
PTAPUE = ~0x81; // osc2 pin is PTA4 I/O
ADCLK = 0x40; // ADC clock= fbus/4
i_LCD();
print_lcds(title);
delay(60000);
now = old = PTA&4;
LCDWI(1); // clear lcd
//asm(" cli"); //enable irq interrupt
for(;;)
{
while(!(TSC&0x80))
;
TSC &= ~0x80; // clear TOF
// PTA ^= 2; // task running ~60Hz so the loop running is 120Hz or 1/120Hz
task_led();
print_distant();
detect_pulse_input();
COPCTL = 0; // clear COP
}
}

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