I have a problem with my self designed pcb which uses the k64f (100 pins) as the mcu. one pcb work just fine. however, the other one cannot be programmed via jtag because the reset_b pin is permanently low. the reset line is connected to a power source via pullup resistor. I have verified that all decoupling capacitors are ok. If I connect the reset pin to a power source, the reset line stays high. thus there is no leak anywhere. however, if I turn on the k64, the reset pin is driven low and stays there. what is wrong???
hope someone can help!
thanks in advance