基于DSP2812平台，CCS3.3，采用事件管理器EVA的T2计数器测定QEP电路脉冲个数，编码器AB相输入到EVA的指定引脚。正转则T2增计数，反转则T2减计数。亲测可用。注意一圈脉冲数为编码器线程的4倍。(DSP2812 based platform, CCS3.3, the event manager using EVA T2 of the counter circuit pulse number measuring QEP, Encoder AB input to the specif