I has been programming using UNO and my project working well. Then I try to switch to breadboard ATMega328P in TQFP is also working well.
But I cant get my program to work on ATTiny85. The same program can run perfectly when I use ATMega328P-CU in TQFP. (Of course when i change to ATTiny, I have change the data, clock, latch pins according to ATTiny85 pin configuration).
My program is just reading the variable resistors and shift out the output into two shift registers of 74HC595. Because i think the number of pins in ATTiny85 is sufficient to run this project, so I do not want to use excess pins in ATMega328P.
The only different i thought is in ATTiny85, I cant have external crystal and I thought is the speed to slow, then I try burn bootloader for the ATTiny to 8MHz, it is still not working even though all upload is perfect. There is no errors.
Could someone experience this tell me what is the different and how to get this work ?