fix error: missing compiler version 5 on Keil
1. Download Arm Compiler 5 link: google drive 2. Install Arm compiler 5 Extract and Run "setup.exe" file. Create new folder "ARM5" inside "C:\Keil_v5\ARM" path. 3. Add Arm compiler 5 into Keil 4. Select Arm Compiler 5 as default References: Arm Compiler downloads index