Arm provides software developers working with Holtek devices based on the Arm Cortex-M0+ processor with a free-to-use professional tool suite.
The free Keil MDK Holtek Edition – Cortex-M0+ edition includes the Arm C/C++ Compiler, the Keil RTX5 real-time operating system kernel, and the µVision IDE and debugger.
If you wish to program also Holtek's Arm Cortex-M3 based devices, purchase the Keil MDK Holtek Edition – Cortex-M0+/M3/M4 online.
Download MDK Core