Hex to Decimal Conversion for Fixed-Point Integers

This page explains how to convert between hexadecimal and decimal numbers in a fixed-point integer format. We’ll provide C code to accomplish this conversion in both directions. The code handles both positive and negative values.

A key aspect of this conversion is understanding the Q format. You’ll need to adjust the value 32768 (highlighted in red in the code) to match the appropriate Q format for your specific application. In the provided example, a Q format of 15 is assumed.

This conversion is particularly useful when working with Analog-to-Digital Converters (ADCs) in communication receiver chains. ADCs often output hexadecimal data, which is then stored in memory. This program allows you to easily convert that hex data into a more readily understandable decimal representation for analysis and debugging.

C Code for Hex to Decimal and Decimal to Hex Conversion

The C code (available for download at the link below) provides functions for both:

• Hex to Decimal Conversion: Converts a hexadecimal number (represented as a string) to its equivalent decimal (integer) value.
• Decimal to Hex Conversion: Converts a decimal (integer) value to its equivalent hexadecimal representation (as a string).

Important Note: As mentioned above, remember to adjust the 32768 value in the code to match your desired Q format. This value represents $2^{15}$, reflecting the 15 fractional bits when using a Q15 format. For a Q12 format, for instance, you would change it to $2^{12} = 4096$.