LCD not displaying RPM

[antony1925]

Hi,

I have been trying this for a long time to display rpm on the LCD but it does not display the rpm.

I initialized rpm to a float variable and a normal text to a character.

The character message displays but not the rpm, is this because I have the rpm in float and I did not convert into string or a character or is there any other problem.

I will attach my code for your reference.

Code: Select all

char *text = "Cadence";
float *Rpm = 0;
unsigned int Rot_time = 0;
unsigned short Pulse_HSL;   // holding falling edge time for start of timing sequence
unsigned int Pulse_HSH;
unsigned short Pulse_EL;   // rising edge for end time sequence
unsigned int Pulse_EH;
//unsigned float Rot_PH = 0;
//unsigned float Rot_PL = 0;
void main()
{
      //Soft_Uart_Init(PORTC,7,6,57600,0);
      delay_ms(500);
      PORTB = 0;
      TRISB = 0;
      TRISD = 0;  //Set all PORTD for output
      PORTD = 0;
      TRISC = 0x02;  //RC1 as input for CCP2
      Lcd_Init(&PORTB);
      Lcd_Cmd(Lcd_clear);
      Lcd_Out(1 ,1 , text);

      INTCON  = 0;  //Disable all Interrupts for initialization of other registers
      T3CON   = 0;  //0000 0000  was $C0 Sets Timer1 as source clock for CCP1 and CCP2 leaves timer3 off
      CCP2CON = 0x04; // set for every faling edge, 05 every rising edge capture
      //CCP2CON = 0x06;  //set for 4th rising edge, $07 Initially Set CCP2 for 16th Rising Edge Capture
      T1CON   = 0x01;  //set for 8 bit time read, prescaler of 1 and turn timer 1 on
      //T1CON = 0x81; // set for 16bit read, prescaler 1 and timer1on
      TMR1L   = 0x00; //zero timer registers
      TMR1H   = 0x00;
      INTCON  = 0xC0;  //Enable Interrupts

while(1)
{
       //delay_ms(100);
        //Soft_Uart_write(Rpm);
      if(PIR2.CCP2IF == 0 && CCP2CON == 0x04) // if flag is set and pulse is trigerred
      Rot_time = (Pulse_EH<<8|Pulse_EL) - (Pulse_HSH<<8|Pulse_HSL);
      Rpm = 240000000/Rot_time;//combining both hi and low byte of rotation period
      Lcd_Out_cp(Rpm);     // Print text on LCD

}
}
void interrupt()
{
      //INTCON.GIE = 0; // clearing GIE to prevent any other interrupts while handling this one

      if(PIR2.CCP2IF == 1)
      {
        switch(CCP2CON)
        {
          case 0x04: // start time of the sequence i.e. falling edge and gets start time
          Pulse_HSL = CCPR2L; // capture pulse high start time
          Pulse_HSH = CCPR2H; // get captured time high byte
          CCP2CON = 0x05;
          PIR2.CCP2IF = 0; // reset the flag
          break;

          case 0x05: // end time sequence so timing sequence complete, calculate time intervals
          Pulse_EL = CCPR2L; // get time of the rising edge
          Pulse_EH = CCPR2H;
          //Rot_PL = Pulse_EL - Pulse_HSL; // rotation time = Pulse time HI + pulse time LOW
          //if(STATUS == 0){ Pulse_EH = Pulse_EH - 1; }
          //Rot_PH = Pulse_EH - Pulse_HSH;
          CCP2CON = 0x04; // set start next timing sequence for falling edge.
          PIR2.CCP2IF = 0;
          break;

          default:  rpm = 0;
         } // switch
       }  // if
       
}   // interrupt

Please help me fix this issue please
Kind Regards
Antony

[antony1925]

HI,

I have tried converting the rpm to string and a character but it doesnot display on the LCD.

When I use sprintf statement which converts it to a string the display shows <null> and doesnot give the RPM.

Code: Select all

while(1)
{

      if(PIR2.CCP2IF == 0 && CCP2CON == 0x04) // if flag is set and pulse is trigerred
      Rot_time = (Pulse_EH<<8|Pulse_EL) - (Pulse_HSH<<8|Pulse_HSL);
      Rpm = 240000000/Rot_time;//combining both hi and low byte of rotation period
      //floattostr(Rpm,buffer);
      sprintf(buffer, "%s", Rpm);     // this is taking lot of ROM locations
      Soft_Uart_write(buffer);
      Lcd_Out(2,1,buffer);     // Print text on LCD
}
}

I have pasted the full code in the previous post and this is the part where I am trying to convert it.

Please help me fix this issue.

Cheers