Hello all , I am new to use A T 9 0 P W M
my circuit meet problem ,hope some one can help me .
attached the related schematic , the PB0,PB1 & out0 ,out1 of mcu are two pairs of PWM ports,the 17th and 18th feet is AVCC and AGND . the A01, A02 ,ADC2, Adc3,ADC6 are all ADC ports. when I powered the MCU by ISP( con6) ,(not connected device to AC220V) the both two PWM work good in testing ;
But when I connect the board to power AC220V,(not connected to ISP programer) there are no PWM signal output, but the voltage of C22 and C23 is near 3.6V in testing, I feel strange and can not understand what happened. could you please give me some tips? thanks a lot.