1. Compilation prompt: \Objects\BH-F103.axf: Error: L6218E: Undefined symbol RCC_APB2PeriphClkCmd (referred from bsp_led.o).

2. Solution:

Check RCC_Apb2periphclkcmd press F12 or right-click to select go to definition of ‘RCC_Apb2periphclkcmd ‘, prompt the following undefined error. This indicates that this function is not defined correctly. The correct definition is “rcc_apb2periphclockcmd”.

3. Summary:

In general, when you encounter this error message, the first thing you think of is that the function is undefined or incorrectly defined. You can’t find the function and reference it.

Reference:

Wrong writing

Correct writing: