I made a circuit where the microcontroller works. I made a duplicate of the same circuit with a working micro, but that circuit does not start and there is no smoke and the PCB is clean (no loose wires touching in bad places) So I suspect my problem is the crystal circuitry.
In my micro setup (as with any other 8051 micro), I have an external crystal connected close to the micro's XTAL1 and XTAL 2 pins and each of those pins are grounded through the ceramic capacitors.
Since I use a socket for my micro IC to insert into, I want to make an in-circuit crystal "tester" circuit so that I can touch probes to the correct metal pins of my micro IC (representing XTAL1 and XTAL2 and GND). I want this tester circuit to distinguish between a working and a non-oscillating crystal arrangement.
I looked up pierce oscillators online and based on schematics, the only way I could see me possibly pull this off is to use some sort of inverter from a logic IC like this:
and hooking up its output to something (555 timer?) to lower the frequency and output that to a speaker so I hear a screech if the crystal works.
Could I use a 74HC04 inverter here to complete the tester without any issues in the inverter not handling the 24 MHz crystal frequency?
Also, what should the maximum length be for the test wires if the wires were at 24AWG thickness before the crystal circuit doesn't function correctly?
For clarification, in my test, C1, C2, and X1 are already soldered on to the target board.