I did do a forum search before posting this and couldn't find anything - so apologies if I'm duplicating a post somewhere.

I don't know if forum members are aware, but there is a specific GPT for the 6502 called "6502 Microprocessor Education".

I stumbled upon it whilst surfing The Western Design ...

In my ongoing exploits to develop my understand of 65C02 related hardware and software (which is an enjoyable pastime in itself!), I've been improving my routines for the Hitachi 20x4 LCD HD44780U module which is connected in 4-bit mode to PORTB of the 65C22. As part of my approach, I had already ...

I'm attempting to understand the 65c22's shift register. In order to do so, I've written a small program to send $0F then $F0 in an endless loop through mode "110" (shift out under PHI2 clock control). However, the output (as seen on my logic analyser) isn't what I expected. I've attached both my ...

You have the option to go to Mouser (https://nl.mouser.com/. I use them in the UK. You'll get bona fides parts from them. The only issue is there is a minimum spend before you get free postage - it'll be around €40.

Dave

Something that has long puzzled me is why anyone would use Intel hex to feed code to a MOS Technology MPU. :? :D
Sheer convenience! My assembler, vasm, can produce the format and the code to upload it is in the forum's code repository (thanks to Ross Archer). :)

At some point I'll reverse ...

My involvement with the 6502 and my breadboard SBC is the love of the journey, rather than the destination (mainly as I haven't set one!).

Consequently, I enjoy attempting to make a "more my own" SBC than the Ben Eater clone I built following his videos. Many forum members have helped me develop my ...

On face value, it strikes me that there are quite a few ways of doing this. A confusing number of options really. What is good practice?
I also appreciate that the will be many different assemblers used by the board members here on 6502.org. That bit, I'm not so much concerned about. For my sins, I ...

15w may be a little low but it would work for typical ICs - where it might be a little slow if soldering larger wires when it might not be able to get enough heat to the joints. Yes - I have experienced this - I was attempting to tin the end of some twisted mains cable the other week. Couldn't get ...

Hi All.

I have a couple of questions.

1) I've made do with a soldering iron I bought from Tandy in the UK around 35+ years ago. It is a Weller SI 15D Soldering Iron (240v / 15w). I've just looked on eBay and someone is selling one - it has "vintage" in the title! :shock:
However, as my ...

I'm guessing there will be a few ways you can do this. With the 6502 having been around for some 50 years now, I would think there have been a lot of clever people coming up with lots of clever ways to validate new builds. What do I mean by "validate"? Well, check it is working and, if not, attempt ...

I will say that your active-low output pin assignments, e.g., /OE , should be declared active-low and controlled with positive logic equations, which is opposite of what you are doing.
Argh!! Yes, you did point this out earlier in this thread. So they should be more like this...
/*
* Outputs ...

Well, it's been a while (Dec 24) since I did my last lot of 6502 tinkering. I ran out of spare time back then (and a little enthusiasm too), but I have a little more time on my hands now, so I'm picking up where I left off. In re-reading my posts to recall what configuration I had settled on, I'm ...

I know it's nearly February, but better late than never.

In life, 2025 will be... interesting for me. In April, I'll turn $3B. At the time of writing, I have one more week of working life left, then I retire. I just felt the time was right. My mother passed away last year at 80 years of age. I'd by ...

Another comment regarding your schematic: you may want to pull up pin 3 (A15) of SST39SF010 so its addresses will match your memory map. This way you don't need to relocate your ROM code to $4000-$7FFF for the flash programmer in order to run it at $C000-$FFFF in actual hardware.
Bill
That's a ...

A few comments about the schematic:
* Why are PHI2 and RWB shown as dashed lines? No reason, really. I was just checking out the features of KiCad.
* You can save a chip by combining 74HC11 function into 22V10. I didn't think I had the available pins left to do this.
* Instead of using AS6C4008 ...