ʾʹõԴ
TIM3 CH1     --   PA5
TIM3 ETR     --   PA8

ʾḶ́
1ϵʱӣRCH 48MHz
2TIM3ͨ1壻
   ETRΪĴԴЧ;
3⵽źЧʱ岨Σ

ע⣺
1ͨ2źŵЧصͨ1ź֮ʱΪDelay
   ͨ1źŵĿΪPulse
                                _____________________________________________
                               |  
  ETR _________________________|  
                                             ___________________________
                                            |                           |
  CH1 ______________________________________|                           |_____
                               <---Delay----><------Pulse--------------->