Oops, my mistake - which one?

... it.

I notice that at one point you use an instruction that is technically not part of the original 65C02 instruction set. It is one of those Rockwell extensions that is included in the W65C02S instruction set, though. It would only be an issue if the processor in use happened not to be a ...

I finally completed the 24-bit version. This probably makes this core much more interesting as it can access 16MB of memory. It has been extensively tested and seems quite stable. See first post for download links (or go to Github).

Version 1.4 changes:
- Extended address bus from 20 bits to 24 ...

... things de-selected (or at least outputs disabled), thus taking less power when you want to get down to microamps.
Referring to Figure 8 from the Rockwell datasheet again, I would need to remove the inverter between the clock and the NAND gate to stop the clock on Φ2 low, correct? (I'm using a 1MHz ...

I'm not sure if the 6500/1 was a MOS design or a Rockwell design, but the Rockwell version has a lot more documentation. This includes emulator devices with a piggyback socket for an EPROM, for development, and I think there is one packaged with extra pins for an external bus for a ROM only. They are ...

... to start and stop the clock. [...]
In the post where I initially talked about this idea , there's a screenshot of that circuit (Fig. 8 ) for the Rockwell chip. OK -- looks good.

Yes, but what is it that provides the cue for the clock to restart?
The ESP32 on which the terminal runs will stop the ...

... and stop the clock. And, to do so cleanly (ie, without the risk of producing partial pulses that can crash the CPU), said circuitry will involve more than just an AND gate.
In the post where I initially talked about this idea , there's a screenshot of that circuit (Fig. 8) for the Rockwell chip.

If I'm reading Rockwell's R65C02 datasheet correctly, it appears that an external device can put the CPU into standby mode by stopping the clock with PHI0 high.
That is true of all 65C02s, and the 65C816. As a bonus, all WDC parts with static cores can be stopped on either clock phase.

If that's ...

... down, if using the W65C02S's SToP or WAIt instruction will bring the dormant power requirement down to a negligible level....
If I'm reading Rockwell's R65C02 datasheet correctly, it appears that an external device can put the CPU into standby mode by stopping the clock with PHI0 high.
stopping ...

... the TSB and TRB instructions...
Those two are also available with the 65C02 and, in my opinion, are more generally useful than the RMB and SMB Rockwell extensions, which have only zero page addressing and can only affect one bit.

As you noticed the "AND #%1111" isn't strictly needed.
Unless ...

Welcome, AlexeyM82... and nice work on the project! :)

Pure nostalgia on my part, but the vintage Rockwell chips are like old friends to me... with many a mile traveled and many a lesson learned. And even now I prefer them in some ways to the modern WDC product.

More concretely interesting is your ...

After a long time I have uploaded the latest version here. This is a fully tested version which also passes Klaus Dormann's test suite.

This version has an improved internal stack which resides in three 256-byte SRAM's. I added TOS/NOS registers so that the access is mostly 0-cycle. In the case ...

... size, not extensibility. Mostly, I consumed too much time trying to work around his kludges. Complicating things was the irregular syntax of the Rockwell extensions, as well as irregularity in the opcode table caused by the addition of the new instructions, which don’t all follow the pattern of the ...

I've also bought some (allegedly) Rockwell 6502 chips from UTsource that - when they arrived - had definitely been sanded and reprinted.

Not sure why as they bothered as they all worked fine.

If you have an XGecu TL866 II then I've written up a small test definition for the 6502: Testing the ...

... n and z , which is not noted in your chart.

ADC affects c , n , v and z , but is only showing that it affects n and z .

Italics indicate the Rockwell bit setting/testing instructions, which in Western Design's 2007 "Programming the 65816 Including the 6502, 65C02, and 65802" are relegated to an ...