ULN2003驱动28BYJ-48步进电机STM32F103库函数版 本实验下载后，电机1先逆时针旋转90度，再顺时针旋转90度。电机2逆时针旋转90度，再顺时针旋转90度。(ULN2003 driver 28BYJ-48 stepper motor STM32F103 register version. After the experiment is downloaded, the motor 1 rotates 90 degre