The Apple II manual was a much better read..
Just found an old Apple II manual in a storage box. Still in pretty good shape. Not a II Plus or IIe manual. The original II. After a quick search found a copy of the Apple I manual online. Its a bit of a head scratcher.
I know 6502 and even rewrote a Z80 monitor and reading through the 6502 source for the Apple I monitor reminds me of the first time I opened up the hardware schematic for the Apple II motherboard and tried to work out what the hell Woz was doing with a lot of the 74 / 74LS lines. About 95% of the 74LS lines where going to the expected places on the board but there were are a whole bunch of lines where it was a - WFT is he doing here. Never did work out some of them.
Then there was the first Disk II we opened up and tried to work out how it worked from the circuit diagram.