A: The compiler itself is not free, but the MDK-Lite edition (32KB code limit) includes it at no cost for evaluation.
A: Yes, but install them into different folders (e.g., C:\Keil_v5_536 and C:\Keil_v5 ). Use the respective project launchers.
This is not an error; it's a feature. If you download v5 specifically for old code, you are on the right track. Issue 4: Windows Defender or Anti-Virus Quarantines armcc.exe Cause: Arm Compiler 5 uses code obfuscation for licensing, which some aggressive AVs flag as suspicious.
| MDK Version | Arm Compiler 5 Included? | Arm Compiler 6 Included? | Recommendation | | :--- | :--- | :--- | :--- | | MDK 5.39 | No (Only AC6) | Yes (v6.19) | | | MDK 5.38 | No (Only AC6) | Yes (v6.18) | Avoid for v5 | | MDK 5.37 | No (Only AC6) | Yes (v6.16) | Avoid for v5 | | MDK 5.36 | Yes (v5.06u7) | Yes (v6.16) | Ideal | | MDK 5.35 | Yes (v5.06u7) | Yes (v6.15) | Also works |
Alternatively, use this direct URL structure (subject to change, but historically stable): https://www.keil.com/download/product/ Here is the critical table. You need Keil MDK version 5.36 or earlier. Version 5.36 was the last release to bundle Arm Compiler 5 by default.
A: Possibly, but you will need to rewrite inline assembly, fix strict enum and pointer type warnings, and test thoroughly. Downloading v5 is the safer short-term solution. End of Article