项目场景：
在使用工程是发现问题：
..\OBJ\OLED.axf: Error: L6218E: Undefined symbol TIM_Cmd (referred from timer.o).
..\OBJ\OLED.axf: Error: L6218E: Undefined symbol TIM_ITConfig (referred from timer.o).
..\OBJ\OLED.axf: Error: L6218E: Undefined symbol TIM_TimeBaseInit (referred from timer.o).
问题描述
Build started: Project: OLED
*** Using Compiler 'V5.06 update 7 (build 960)', folder: 'D:\Keil_v5\ARM\ARMCC\Bin'
Build target 'OLED'
linking...
..\OBJ\OLED.axf: Error: L6218E: Undefined symbol TIM_Cmd (referred from timer.o).
..\OBJ\OLED.axf: Error: L6218E: Undefined symbol TIM_ITConfig (referred from timer.o).
..\OBJ\OLED.axf: Error: L6218E: Undefined symbol TIM_TimeBaseInit (referred from timer.o).
Not enough information to list image symbols.
Not enough information to list load addresses in the image map.
Finished: 2 information, 0 warning and 3 error messages.
"..\OBJ\OLED.axf" - 3 Error(s), 0 Warning(s).
Target not created.
Build Time Elapsed: 00:00:00
解决方案：
前提保证自己的函数工程都没问题，不存在什么写错函数名的一类问题，建议你尝试我这种方法解决：
其实就是忘了添加 stm32f10x_tim.c 文件
