Do one thing buddy. I see that you have written a step:
Actually you should enable the internal pull up resisters on PORT B to get output @ PORT B which would be done by clearing the MSB of the OPTION_REG. So the value for OPTION_REG will be 0x04.
Then,
to set the PORT A pins as analog8/digital pins, there is a register called ADCON1 & ADCON0 is used for which channel to select for ADC to work. Also change ANSELH to ADRESH.
Refer the data sheet for 16F87XA for more details & simulate once again the code & see whether it is working or not.
Regards,
Jerin. ;-)
hi, there is no problem with A/D
i have connect lcd with circuit , but i think there is problem in
calculation of heart rate , c the code plz and till me if u found any thing important
/*Header******************************************************/
// LCD module connections
sbit LCD_RS at RB4_bit;
sbit LCD_EN at RB5_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
sbit LCD_RS_Direction at TRISB4_bit;
sbit LCD_EN_Direction at TRISB5_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
// End LCD module connections
unsigned inputsignal=0;
unsigned int firstRun = 1;
unsigned int cnt=0; // Define variable cnt == 1KHz clk
long HR=0;
char *text;
unsigned char outlcd;
void interrupt() {
cnt++; // Interrupt causes cnt to be incremented by 1
TMR0 = 194; // Timer TMR0 is returned its initial value
INTCON = 0x20; // Bit T0IE is set, bit T0IF is cleared
}
void main() {
Lcd_Init(); // LCD display initialization
Lcd_Cmd(_LCD_CURSOR_OFF); // LCD command (cursor off)
Lcd_Cmd(_LCD_CLEAR); // LCD command (clear LCD)
OPTION_REG = 0x84; // Prescaler is assigned to timer TMR0
ANSEL = 0x02; // Pins AN1 is configured as analog
TRISA = 0xFF; // All port A pins are configured as inputs
ANSELH = 0;
TRISC = 0; // All port C pins are configured as outputs
TRISD = 0; // All port D pins are configured as outputs
PORTC = 0x0; // Reset port C
PORTD = 0x0; // Reset port D
ADCON1.F4 = 0 ; // VSS voltage reference
ADCON1.F7 = 1 ; //A/D Conversion Result Format Select bit adfm=1
ADCON0 = 0x07; // A/D is enabled and AN1 is analog input
text = "instantaneous"; // Define the first message
Lcd_Cmd(_LCD_CLEAR);
Lcd_Out(1,2,text); // Write the first message in the first line
text ="heart rate test";
Lcd_Out(2,1,text);
delay_ms(1000);
delay_ms(1000);
delay_ms(1000);
delay_ms(1000);
delay_ms(1000);
Lcd_Cmd(_LCD_CLEAR);
text ="1)connect";
Lcd_Out(1,1,text);
text="electrodes";
Lcd_Out(2,1,text);
delay_ms(1000);
delay_ms(1000);
delay_ms(1000);
Lcd_Cmd(_LCD_CLEAR);
text ="2)relax please";
Lcd_Out(1,1,text);
delay_ms(1000);
delay_ms(1000);
delay_ms(1000);
while (1){
inputsignal = ADC_Read(1); // Result of A/D conversion is copied to inputsignal
portd = ADRESL;
portc = ADRESH;
if (inputsignal>=600) {
delay_ms(500);
if (firstRun==1)
{
firstRun = 0;
cnt = 0; // Variable cnt is assigned a 0
TMR0 = 194; // Timer T0 counts from 194 to 255
INTCON = 0xA0; // Enable interrupt TMR0
}
else {
//find heart rate
Lcd_Cmd(_LCD_CLEAR);
text="Heart rate=";
Lcd_Out(1,1,text);
//number of interrupt is time between two pulses in ms
HR=60000/cnt;
outlcd=HR/100 ; //hundreds digit in HR
Lcd_Chr(1,12,48+outlcd); // Write result in ASCII format
outlcd=(HR/100)%10;//tens digit in HR
Lcd_Chr_CP(48+outlcd);
outlcd=(HR)%10 ;//ones digit in HR
Lcd_Chr_CP(48+outlcd);
Lcd_out(2,5,"puls/min.");
//rest vlaue of counter
//and start next test
cnt = 0 ;
TMR0 = 194; // Timer T0 counts from 194 to 255
INTCON = 0xA0; // Enable interrupt TMR0
}
}
}
}