EmberZNet/EM35x/app/Driver/TWI
1. NEW: twi_rd() is finished.
EmberZNet/EM35x/app/Driver/TWI
1. CHG: twi_wr() function is finished.
EmberZNet/EM35x/app/Driver/TWI
1. CHG: use polling mode instead of interrupt when WR/RD TWI.
EmberZNet/EM35x/app/Driver/TWI
1. CHG: TWI peripheral is work well when frequency is from 1000hz to 400khz, have been verified with LM73 and TSL2550.
EmberZNet/EM35x/app/Driver/PWM
1. CHG: make pwm module more clearly.