Preliminary pre-testing notes:

• The NOR Flash LSB address bit and deduced a ~1.8 MHz clock speed. The chip is rated for 5 MHz tops if memory serves. If the clock speed is linked to then I see a ~2.77x top speed from the overclock
  • Thus ~37.8 MHz before FLASH reads/writes becomes unstable
  • SRAM possible max of 28-30 MHz may become the limit
    • Depending on what errors occur and when, a switchable overclock may be in order
• Link signal is a bit strange and unless errors are thrown, I'm not going to investigate it further. It's a standard, kinda dirty 3.3V signal level shifted to 5V ptp, but with the intentional capacitance added to the level shifting the signal is distorted making it difficult to discern a 1 from a 0
  
  • More details here: https://www.ocf.berkeley.edu/~pad/faq/xfer.html#5
  • My ignorance in logic analysis will impede the results of overclocking if I dive into figuring out the protocol explicitly if no errors are generated.
• The duty cycle of the CPU clock is 55% high, 45% low
  • There is a glitch in the rise of the clock signal for the CPU that happens in 7074 out of 65000 waveforms, ~10.88%, though it is between a 2% and a 3%

• If the threshold is 3% of greater, all waveforms pass.
• This type of information will be useful for comparing signal quality of the output clocks if instability is seen, though on a lower sample population
• The 45 ns SRAM chips are performing without error and will be used permanently as they consume less power
• The 1.43 kOhm resistor is swapped out with one that has known tolerances
• Standard 63/37 solder paste will be used and pads will be cleaned and paste reapplied between each capacitor swap.
• Previous rise and fall times and plots were made without a ground spring on the scope probe. Errors introduced have now been accounted for since I have ground springs despite Amazon's inability to do arithmetic.
  • The fall time of the RC oscillator of ~44.4 ns remains constant
  • The rise time of ~28.9 ns is now reporting as 34.4 ns
  • A 652 mV ptp triangle wave is observed vs the 940 mV ptp.
  • FFT still reported -12.8 dB at native frequency

Photos and results will be posted within the next day or so as long as time permits