HEX Diff: Compare Two Calibration States Parameter by Parameter
A HEX diff at byte level shows that something changed — but not what. VersaCal therefore compares two states parameter by parameter, with physical values, unit and delta.
Why a Byte-Level HEX Diff Is Not Enough
A HEX file is an image of ECU memory. A classic diff tool compares addresses and bytes inside it. The result is correct, but useless in review.
Because nobody argues about 0x0800 instead of 0x0780. People argue about 12.5 degrees instead of 11.7 degrees. For that translation the comparison needs the ECU's A2L description.
What the HEX Diff Shows in VersaCal
VersaCal lays both states over the same A2L and decodes them. A list of the changed parameters then appears. Every row names old value, new value, unit and delta.
- Physical values including unit instead of raw values
- Delta per parameter, absolute and relative
- Jump back into the original line of A2L source
- Jump back onto the address in the memory image
- Curves and maps drawn as a line or a surface
Which States You Can Compare
The comparison is not limited to two finished files. Likewise you compare the open draft against its predecessor. Thus you see your own work before anybody else does.
Two series states can be set against each other as well, for instance before and after a trial. Moreover, the same comparison appears automatically in every change request. So the reviewer reads exactly what you changed.
Understanding Curves and Maps
For a scalar, one number is enough. A map, on the other hand, rarely changes in a single spot. Therefore VersaCal shows the shape and not only the cells.
You see whether an axis has stopped running monotonically. Jumps and outliers stand out as well. The anomaly scanner marks those spots, and the AI assistance explains them.
From Comparison Into Your Records
A comparison rarely ends in the browser. It moves into a release, a protocol or a form. VersaCal therefore exports the result into the formats your chain expects.
Delta DCM hands over exactly the changed parameters. CDFX serves standardised OEM processes. In addition, CSV covers further processing and PDF covers the records.
Read the standards: ASAM MCD-2 MC
Frequently asked questions about HEX diff
Do I need the same A2L for a HEX diff?
For a direct comparison yes, because addresses and conversions have to match. If the A2L levels differ, the route goes through porting. VersaCal then maps the parameters and lists new, removed and renamed ones.
Are S-Record files supported too?
Yes. Besides Intel HEX, VersaCal handles Motorola S-Record. Results go back out in both formats as well, so your existing tool chain keeps working unchanged.
Can I see unchanged parameters as well?
Yes, the comparison can be switched. By default VersaCal shows the changes, because those are what count in review. For a full check, however, you bring the rest of the dataset into view.
Run a HEX diff on two of your states
Bring two HEX images and the matching A2L. In the demo we build the comparison live and walk through the hits.