mcu pulling clock amplitude down?

[ftransform]

So i have a PIC16 MCU receiving a SPI clock signal.

For some reason the clock signal is being pulled down in amplitude (from 5V to 2.5V when it is connected.
I thought that there was maybe not enough drive current, so I put two 74HC04 inverters in series to make a buffer and I passed my signal through it. When connected to the MCU the signal was even lower, like 1V.


Is there some kind of mis-configuration that can lead to this problem or is the chip fucked? Why would giving it a higher current drive the signal voltage down even lower? wtf!

[Rerouter]

how are you measuring the signals?
do you have some glitch in your code forcing it to output low?

also as those buffers can sink 25mA, what can your chip supplying the clock feed supply?

[ejeffrey]

Are you sure the SPI clock is configured as an input rather than an output?

Are you sure the wiring is right?  Are you using a solderless breadboard?  If so, check for bad contacts, especially to the supply voltage.

Probe other points in the circuit.  Does the supply pin of the inverter chip drop to 1 V?  Are the ground pins actually at 0V?

Typically when building a circuit for the first time, guessing a chip is bad should be your last resort unless you know you have done something to destroy it (like reverse the supply polarity).  It is always far more likely that you have made a mistake.

[ftransform]

oh stupid me, i think it was set in master mode
i need to take up medidation or something electronics make me so angry i cant think

[glatocha]

I have a simple working solution. When you stuck, go for a jog. I will reduce the tension and might bring you the solution.

[ftransform]

I have a simple working solution. When you stuck, go for a jog. I will reduce the tension and might bring you the solution.

lol, ice cream