When writing code with Keil software, the first step is to select the main chip. If the firmware library corresponding to the main chip is not installed in your Keil software, the corresponding main chip will not be selected, and the subsequent programs cannot be compiled successfully. At this time, you need to download the corresponding firmware library on the Internet. The best choice to download the firmware library is to download the official firmware library on the Keil official website. The specific operation is as follows: (Of course, you can skip the following operation and go directly to the website: https://www.keil.com/dd2/ and select the chip firmware library package you want)
Take the STM32F103C8 main chip firmware library as an example below
The first step is to open the homepage of Keil official website http://www.keil.com/ , ①Left click Products; ②Left click Device List.
The second step, ③drop down to the bottom to find STMicroelectronics, left click.
The third step, ①Left click on STMicroelectronics; ②Left click on STM32F1 Series; ③STM32F103; ④Select STM32F103C8.
The fourth step, ①click Download
