Delete comment from: Ken Shirriff's blog
Perfect timing for this article: I was starting practicing some chip RE basing on your first one on nanoprocessor.
May I ask for your interpretation of a couple of mysterious (to me) objects on the chip, please?
The first is in the clock/control circuitry, at coordinates (8500,500) in the PSD file. It looks like a pad but it's not. Could that be a kind of capacitor to time the reset pulse? The NP has no external reset signal and it must generate it internally when supply voltages rise.
There are other funny looking objects that are only used for D7-D0 lines, one is at (10250,1560).
My guess is that they are some kind of protection diode.
Thanks for your hints.
Sep 20, 2020, 5:28:02 AM
Posted to HP Nanoprocessor part II: Reverse-engineering the circuits from the masks