Hello Sir. I have designed a new PCB using STM32L151C8T6 micro-controller. I am trying to run my PCB using STM32F429 discovery board. I have made the following pin connections of my PCB with the discovery board : VDD (3V), SWCLK, SWDIO and GND. I am using ST Link Utility (NOT A JTAG CABLE) to program the board. The core mounted on my PCB is successfully being detected in Keil Target Configurations but I am not able to download the program into Flash. I am getting the error as "Could not Stop Cortex-M device! Please check the JTAG cable" I changed the debug settings into the target options as: Connect - "under reset " and Reset- "HW Reset". Then I started getting error as "Core is held in reset". I have Boot0 pin of STM32L151C8T6 which I connected with GND (as per the Boot Configurations in Reference Manual) via a pull down resistor. But could not download the program. I also tried pull Boot0 pin up via pull up resistor but getting the same errors. Please let me know how could I solve these errors or what configurations are required to be changed.