Byte Sequence and Offset Practice
Use this synthetic sequence to practise locating a byte. It is invented for learning, not ECU data.
Locate a byte
An offset locates a byte; it is not the byte
Synthetic four-byte sequence. Each card separates its zero-based position, hexadecimal byte and optional unsigned-decimal view.
- Offset
0x00Hex byte12Unsigned decimal: 18 - Offset
0x01Hex byte2AUnsigned decimal: 42 - Selected example Offset
0x02Hex byte80Unsigned decimal: 128 - Offset
0x03Hex byteE0Unsigned decimal: 224
Text equivalent
The synthetic sequence contains four ordered bytes. Offset 0x00 contains hex 12 (unsigned decimal 18); offset 0x01 contains 2A (42); offset 0x02 contains 80 (128); offset 0x03 contains E0 (224). The selected example is offset 0x02. Decimal values use an unsigned-byte interpretation and do not establish what the bytes mean in a file.
Describe what you know
The sequence establishes positions and displayed values under the stated rule; it does not say whether a byte has units, belongs to a larger field or has a particular software meaning. Those answers need format and surrounding context.
Check the conversion with the Hex to Decimal Converter. It converts a number; it does not infer a byte’s width, signedness or file meaning.
Changing 80 to 81 in a copy would make the byte sequence different at offset 0x02. It would not show that the change is a meaningful calibration edit or predict a real-world effect. No real file needs to be edited to complete this practice.
Continue the learning path
- Review bytes, hexadecimal and offsets in the foundational guide.
- Apply the same distinction between observations and interpretation in Working with Raw ECU Files.
- Continue to Generic Checksums: Additive Modulo 256 and XOR for two generic byte calculations and their limits.
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