Stm32l152 Keil Development Environment display internal command error flash down

Use the Keil development environment to develop the release L discovery. After firmware is updated, the target board cannot be connected. The error "Internal Command error flash download failed target dll has been can" is returned. Finally, update Keil to 4.60.

During use, when the target board chip is in sleep state, the internal command error flash download failed target dll has been can error will also occur when trying to connect to the target board, the solution is to disable the target board from sleep, that is, press and hold the reset key to download the program.