I own several AT89C4051 microcontrollers and I'm currently trying to read signature bytes of the micros that I probably broke (by applying 7.2V to the VCC pin before noticing the 5V regulator became a short circuit between input and output) and I want to read signature bytes of the good micro.
Currently I use an RC setup (1uF pull-up electrolytic capacitor + 10K pull-down carbon-film resistor) on the XTAL1 pin and short the capacitor as attempt to increment the clock by one pulse but I feel this isn't the best approach because the voltage at XTAL1 would slowly fall in voltage and that might confuse the micro.
I read how schmitt triggers and flip-flops might rectify this, but I'm looking for something simple without alot of part count. I mean I could go with a 74HC14 but I'll be wasting 5 out of 6 gates in the package.
Whats the simplest way using the fewest parts to create a clean clock signal without relying on an ultra slow oscillator? I want to increment manually with a button.