i read value from the ADC, and I stored it in an unsigned char
uint8_t Sample_a = ADCH;
Then I want to calculate the input voltage
double voltage = Sample_a*0.01953 (5 volt the reference and i use 8bit)
When I check the time in the debugging mode it turns out 0.2ms is required to make only this calcaultion (CPU 4MHz).
Anybody has a suggestion how can I made this faster?