How to return ADC_Read() as characters in PIC ? Using mikroC PRO?

Question

We have a function:

unsigned int ADC_Read(unsigned char channel) {
    if (channel > 7) //If Invalid channel selected
        return 0; //Return 0
    Delay_ms(2);
    ADCON0.GO_DONE=1;
    while (ADCON0.GO_DONE); //Wait for A/D Conversion to complete
    {
        return ((ADRESH << 8) | ADRESL); //Returns Result
    }
}

It returns the binary value from ADRESH register as an Integer. But we need it as a character, since our Soft_UART_Write() function only accepts characters as parameters, and we need to print the values to the UART. So how can we make this function return characters? For example, if we get input as 01000010, it should return 'B' Refer here. I also tried functions like itoa(), but I get:

There is not enough ROM space adcuart.c

Since I'm using UART Library, there seems to be no space. So I'm looking for a direct or more efficient way to convert it.

Answer 1

The itoa() function can be used but since it's not a part of neither native C nor C++, it may not be defined in your compiler. Anyway, here's how it's used:

#include <stdlib.h>
char aADCValue[10];
unsigned int uiADCValue;
...
uiADCValue = ADC_Read (numChannel);
itoa (uiADValue, aADCValue, 10); //converts the number uiADValue in decimal-base.

If itoa() is not defined in your compiler then you need to convert each digit to ASCII char:

char* myitoa(int num, char* str)
{
    int i = 0;
    char t;

    // Handle 0 explicitely, otherwise empty string is printed for 0
    if (num == 0)
    {
        str[i++] = '0';
        str[i] = '\0';
        return str;
    }

    // Process individual digits
    while (num != 0)
    {
        int rem = num % 10;
        str[i++] = (rem > 9)? (rem-10) + 'a' : rem + '0';
        num = num/10;
    }

    str[i] = '\0'; // Append string terminator

    return str;
}

Another solution can be sprintf() function:

#include <stdio.h>
char aADCValue[10];
....
uiADCValue = ADC_Read (numChannel);
sprintf (aADCValue, "%s", uiADCValue);