It's quite a complicated area. The only official notation is what's drawn on the 6502 schematics, which are not public. Donald Hanson's block diagram is drawn up as his best understanding, at the time, of what was on the schematic. The notations in visual6502 are not precisely the same, because ...

Donald F. Hanson drew his 6502 diagram. A block of timing generation logic has 8 registers: T0, T1, T1X, T2, T3, T4, T5, and T6. This Visual 6502 shows that timing generation logic only has 7 registers, but not 8 registers. I have no idea where T1X comes from or it does not have storage. Perhaps, T0 ...

It worked! Thank you for sharing this source code.

Take care,
Bryan

I use Magnifier which it comes with Windows 10. I enable inversion. The Visual 6502's colors on this browser does not match my sight. I know how to change the colors by modifying rgba's values in expertWires.js and Wires.js.

I am unable to find the rgba's value for background. After Magnifier's ...

The label of phi2 in the 6502 MPU's pinout is actually clk0. It is supposed to be inverted phi2. If the line is pulled low, then cp1 (710) goes high and cclk (943) goes low. To complete one clock cycle, cp1 (710) goes low and cclk (943) goes high during phi2 is high before cp1 (710) goes high and ...

So, if your circuit needs non-overlapping clocks, it's not enough to invert a clock and call that the inverse. What you do is use some cross-coupled gates, which allows a rising edge on each clock only when the other clock has gone to zero.

The 6502 does have an on-chip non-overlapping clock ...

Sorry, I don't understand well enough what you're writing to help - I was responding to your image. If you tie together the outputs of two inverters, in MOS technology, you have a NOR gate.
Hi Ed,

Sorry, I could do my best in trying to explain what I am referring metastable value. My ...

What you have there [in the diagram] is something like a wired-NOR. The two pullups are in parallel, so they will act as a single, larger, pullup. So that's the logical function of a NOR, slightly more resistant to pulling down because more eager to pull up, and therefore the electrical threshold ...

I remembered that we had discussed accumulator register couple months ago. They may agree or disagree whatever they think 1 win-win or 0 win-win. I will like to revisit the discussion today.

I omit the pass gate transistor from top transistor's output and bottom transistor's output on the shared ...

I talk about 65816 microprocessor. ASL, LSR, ROL, ROR, INC, and DEC do not have long absolute addressing. Can you please provide me an example of your code how they can use 24 bits address bus instead of 16 bits address bus. The only alternative option is to load data bank value into accumulator ...

I wonder why STA instruction takes five clock cycles when it DOES NOT cross the page boundary. If invalid address shows from crossing the page boundary on the address bus, then R/W signal is ALWAYS read only during clock cycle 4 before it is switched to write only during clock cycle 5. It is good ...

Hi,

I asked about Control Flip-Flops in Random Control Logic last year. Six latches are POS, NOCR, SD1, SD2, CS, and I/V. Nobody knew the answer. After I completed analyzing Visual 6502, I believe I finally know the answer.

I/V is set overflow to Processor Status Register's Overflow flag. The ...

(I'm going on vacation soon so won't necessarily be quick with a reply)
I hope you have a wonderful time on your vacation soon.


I've no special preference for yellow pass transistors, but using blue when you have blue wires and other transistors have different colours is confusing. I'm quite ...

If you change the background to white, you may need to change other colours to darker shades.
I keep few colors in my table. I continue to draw the schematic in black background. It helps to keep my eyes getting tired at looking white background. After the schematic becomes final, it can be ...

Hi Ed,
Which is better do you like A Reg1/2.png or A Reg3/4.png? the simpler transistors in images 2 and 4 are much better.
Do you like both image 2 and image 4? Which size of image 2 or image 4 do you prefer? As for the dark labels, no, sorry, I can't see them. Only with the monitor turned up ...