How to build a 6502 TTL-CPU: Part 5 Program Counter

This is part 1/2 of the program counter design and bring-up.
In this video, I do a deep dive into Ben Eater's program counter design, then modify it for the SAP6502.

The SAP6502 is a nine part series.

[mheermance]

I like the random video clips you insert randomly. It adds a bit of levity and avoids too dry a presentation, although I would watch without them as well.

[mr_noodler]

Beautiful❤ so awesome! I’m just getting started 6502 assembly programming green and I’m looking forward to building a machine

[galier]

Awesome. A real pity you don't get the views at the level ov Ben Eater.

[bryede]

Huh, $1A performs a NOP on a real 6502 ($EA being the official NOP opcode) so I don't know why you'd use it, unless it's some kind of breakpoint marker in the development environment.

[mheermance]

While I understand what active low logic is, it has always bugged me. I've assume there's an underlying hardware reason, like reducing the number of gates, or preferring nand logic. But I don't really know why.

[abrahamjushua]

Hi, a question : How the 6502 MP handles the interruptions(NMI and the IRQ) at the hardware level ?

[WaldoHazeleger]

About the difference between latch (373) and flipflop (374). Isn't it true that Ben's design "wins" the cycle back because the eeprom decoding (next step counter) happens on the falling edge of the clock (inverted clock)?
The eeprom has time to settle until the clock rises again.

[vanhetgoor]

Although this is way above my comprehension, vaguely I am beginning to understand how a processor could work. Still I can't reproduce a 6502, don't worry AliExpress had one for me.