I need to help i am working with stm32f10x Discovery Board with st-link debugger first time it connect with target device its works 2 3 days but now it not connect with target device message showing DDL have been cancled.
Can you connect to the target using the ST-Link Utility from ST?
www.st.com/.../stsw-link004.html
If that can't connect, then the problem clearly has nothing to do with Keil.
When the ST-Link Utility fails to connect, it gives some hints on things to try ...