Been stuck on this initialization problem for a while...
I have a master MCU and a slave chip. The MCU pulls a /RESET GPIO pin low on the slave for a full second, then pulls it high, then waits for a ready signal from the slave. My problem is on first power up, the MCU never receives the ready signal - it's waiting for the slave to be properly reset. I know the /RESET pin is going low and then high as it should by measuring the pin's voltage during the initialization...
However, if I manually jump the salve's /RESET pin to a ground trace on the board for a moment, and release the jumper, then the slave will boot and send the ready signal! And the slave will continue to be reset fine from the MCU thereafter until power is removed from the system again, and another initial boot is required.
I have tried tying the /RESET trace to ground via 100k ohm resistor, as well as to VCC.
I don't know where to start diagnosing this, so thanks in advance for any comments.
Context: Board is a two-layer PCB I designed myself. SMT components. I am in no way a professional at circuit design..