Latest Versions

Download the latest Keil software products.

MDK-ARM Version 4.22a (September 2011) Development environment for Cortex and ARM devices.	C51 Version 9.05 (August 2011) Development tools for all 8051 devices.
C166 Version 7.05 (August 2011) Development tools for C166, XC166, & XC2000 MCUs.	C251 Version 5.07b (August 2011) Development tools for all 80251 devices.

Keil products use a License Management system - without a current license the product runs as a Lite/Evaluation edition with a few Limitations.

Previous Versions

Enter a valid Product Serial Number (PSN) or License Code (LIC) to get access to all product versions available to you.

Further information about installing your software is available in the Read Me First brochure.

Notes Note

Use a current Product Serial Number (PSN) to get a License Code (LIC) that converts the Lite/Evaluation version to a full edition
Evaluation editions of Keil software products do not require a Product Serial Number or License Code.