I'm observing CLK stay low during the chip probe. I was hoping to see a
   square wave.
   Makes sense to look at the source as see where CLK is used, I think.

   On Tue, Apr 5, 2022, 6:40 AM Undiscussed Horrific Abuse, One Victim of
   Many <[1]gmkarl@gmail.com> wrote:

   My arduino flasher, although I appreciate it, is running into the same
   issue as the teensy flasher. It says there is no chip when one is
   there.
   I've reseated connections that look loose. I've replugged the usb
   cable. I've reseated the flash chip and verified it's not backward.
   I've tried a 10uF capacitor instead of a 100nF. I've put tape under the
   arduino in case it's shorting on something below it. Same behavior.
   I've also labeled the lines! And plugged in my oscilloscope and wired
   its probe ground to the board ground.
   Plan is to plot the clk line just to get comfortably with measuring a
   logic line.

References

   1. mailto:gmkarl@gmail.com