Read IHEX File: Understanding the Binary and Inverse Complement

The Intel Hex (IHEX) file format is a standardized way to store binary data, typically used by device programmers to program microcontrollers with compiled code. This article will delve into the details of how to read an IHEX file, convert its contents to binary, and apply the inverse complement technique.

Each line in an IHEX file follows a specific layout, starting with a colon (:) followed by the number of data bytes on the line. The first two characters represent the type of record: '00' for data and other values for different types. Next comes the 2-byte address, represented by four characters, ranging from 0x0000 to 0xFFFF.

The data bytes follow, with each byte consisting of two characters. The line ends with a checksum, which is the 2's complement of the sum of the number of bytes, address, type, and data. This ensures that errors in transmission or storage can be detected and corrected.

To read an IHEX file, we need to understand how to convert its ASCII values into binary data. Each line must be parsed carefully to extract the relevant information: the number of data bytes, the address, record type, and data.

Here's a step-by-step guide:

1. Identify the first two characters, which determine the type of record.

2. Extract the 2-byte address from the next four characters.

3. Determine the number of data bytes on the line based on the initial value.

4. Read the data bytes, converting each pair of characters into a single byte.

5. Calculate the checksum by adding up the number of bytes, address, type, and data, discarding any carry to obtain an 8-bit total.

The resulting sum is the 2's complement of the inverse of the original sum, which is achieved by inverting each digit (adding 1 to it). This process converts the original binary value into its 1's complement representation.

In conclusion, reading an IHEX file requires a thorough understanding of its format and the steps involved in converting ASCII values to binary data. By applying the inverse complement technique, we can ensure that errors are detected and corrected, making it an essential tool for device programmers working with microcontrollers.

Read ihex file