The /P=Q output from the F521 looks like it's only connected to the HCT138 and HCT139. They're both TTL level inputs so it will be fine.

Just as BigEd has said, there's a lot of enthusiasm on this forum. And a scary amount of experience. The advice you get is gonna be good but ... not always suitable. A 1Mhz 6502 build is not a finicky build; you'll absolutely be able to do the one you've sketched out on a bread board with HC/HCT ...

I'm probably the wrong person to ask as I went all in on LVC - I wanted minimum propagation delays out of discreet ICs.

I like speed. But as a hobbyist with no real background in electronics the lessons were pretty rough.

I think mouser stock the AHCT 138 and AHCT139; and also the AHC 138 and ...

If you haven't placed your order yet Mouser do stock the SN74F521N which is a dip from the F family and is only a nanosecond or two slower than the FCT variant. If memory serves it pulls all the way up to about 4.5V so it should play nicely with HC chips.

[edit] apologies - memory did not serve me ...

According to https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html, the ed25519 key type is supported in puttygen since PuTTY 0.68, released 2017-02-21 Thanks for pointing that out.

Following the Windows 11 debacle I've since moved to Linux and so am no longer using Putty but still ...

Two thoughts occurred to me off the top of my head.

Instead of using a 74HC137 you could instead use the faster 74AHC138 as you're using the latch in transparent mode (/LE tied to ground)

I'm not sure the NAND gate U7C is entirely working as expected. If the address decoding generating /bankcs ...

Very cool, which device did you target? I'm assuming an EPM570 or something. And do you have a public repository for the Quartus II project?

What size screen is that? 7"?
I recently got a 9" RA8875 from BuyDisplay and it doesn't work :(
Yes, it's a 7" display. I had to rewire all of the jumpers to get it to work in 6800 // mode, it was hard-wired for 8080 mode. I followed the diagram to the letter, and presto! the beast came alive ...

Speaking of lens separation, this is the setup I'm using:Which gives plenty of room for soldering. The microscope is just cable tied to a desktop microphone stand; as are a couple of flexibe LED lights.

Right! back to the RA8875

Someone mentioned one a few days ago that looked interesting, but I can't recall where...
edit: the search function... :roll: This one: https://www.amazon.com/dp/B08GSS1WLX Might have been me, or maybe not. I don't remember. Either way I'm using that digital microscope and it's really capable for ...

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 ...

Nice, that's looking good!

I'm enjoying watching this progress, I just don't have anything useful to add but I hope you keep it up

Cheers, Andrew

I wish I could as I keep looking at the '265 and thinking "that looks useful". And then dig into the datasheet and kinda go "yeah, nah" and go back to the '816

Quick question: is the parallel interface bus a '265 specific thing or is it just a pair of '265s on the same parallel bus?

Happy new year to you and everyone on this forum! (I hope it's a good one )

HCP65 Processor Board.jpg ... well maybe a bit of context. The W65C816 is the only chip oriented at 45 degrees.

Does it work? Nope. That's next years problem. And as you can probably see by some of the board revision numbers I'm collecting a bit of a graveyard of failed attempts.

HCP65 Tester ...