UART + ADC float problem

[mostafa328]

Hi

Im having trouble with my coding, i can't get my output to display as "00.0". Instead it displays via UART teminal as "27.99999", where it should display as "02.9".
I also tried sprintf instead of floattostr but it displays nothing. Unless i did something wrong. Im using pic18f4680 and mikroc pro. Can anyone point out what im doing wrong The following is my code:

unsigned int adc_rd;
float value;
char text[15];


void main() {
CMCON =7; //disable comprators
ADCON0 = 0b00001001; //select analog 2 and enable ADON
ADCON1 = 0b00001011; //Use VDD and VSS as reference voltage and pin 2 as analog
ADCON2 = 0b10001010; //Right justified, 2TAD, FOSC/32
TRISA = 0xFF; //TRIS A all inputs

OSCCON = 0b01110000; // 8Mhz internal oscillator
UART1_Init(9600); // baud rate at 9600bps
delay_ms(100);


while(1)
{
adc_rd = ADC_Read(2);
value =(adc_rd*50)>>10 ;
text[0] = value/100; //extract hundreds digit
text[1] = (value/10)%10; //extract tens digit
text[3] = value%10; //extract ones digit

floattostr(value,text);
// sprintf(text,"%u.%01u\n",d1,d2,d3);
UART1_Write_Text(text);

delay_ms(2000);

}
}

 

[androidbuddy]

First of all you can not use floating point value with mod(%) .
you need to type cast before storing into the char array.
that is as below.

text[0] = (char) value/100; //extract hundreds digit
text[1] = (char)(value/10)%10; //extract tens digit
text[3] = (char) value%10; //extract ones digit

try this.

It may work.
If it does not work than come back here with your need error.

thankz,
androidbuddy

 

[Kpatel_IPR]

HI,

adc_rd = ADC_Read(2);
value =(float)(adc_rd*50)>>10 ;
value on LHS is float where as RHS is evaluated as int and then assigned to float so this may truncate the result