The J64C (version 0)

[J64C]

Cool thanks!

When you say 10% to 90%, do you mean 0.5v to 4.5v in this case? Just to get a better understanding on standard terms.

[J64C]

So more like this?

I almost feel like I'm not at the level I need to be to participate in this particular forum.

[GARTHWILSON]

J64C wrote:

So more like this?

Yes.

[J64C]

GARTHWILSON wrote:

Yes.

Yes on both fronts of my post?

[BigEd]

J64C wrote:

I almost feel like I'm not at the level I need to be to participate in this particular forum. :oops:

Hee hee - it's a joke of course. But just to be clear, there's no minimum level of competence needed here. There might be a minimum level of willingness-to-learn, of course, which might mean a minimum level of humility. And sometimes, someone will ask a question which is quite deep, and it can be very difficult to give an entry-level explanation. Sometimes, the best explanation (at a given level) is not a fully truthful one, because the truth is messy and full of little details. And sometimes, often, there are matters of judgement and personal preference, in which case there can be several different correct answers.

The most difficult questions of course are the ones which encode some misapprehensions - it's necessary to unpick the misapprehensions before getting to the truth of the matter.

[BigDumbDinosaur]

J64C wrote:

I almost feel like I'm not at the level I need to be to participate in this particular forum.

We all started at that "level." Excepting maybe Garth, none of us was born knowing this stuff.

[J64C]

Thanks guys! This does actually make me feel better.

I'm the first to admit that I have lots to learn. But, what I do learn, I try to learn as well as I can. I'm not one to take short cuts. And if I do take short cuts (in someone else's eyes), it is more than likely it's because I don't know any better, at the time. I try to do everything to the best of my ability and take pride in what I do. That can sometime come across as arrogance, but I assure you it's purely excitement. I often run around the house with circuit boards I have just made, showing my kids "the awesomeness!! ". The kids just roll their eyes and say "yeah, great Dad... ". Haha!

My background started out as an apprentice in electronics, servicing office equipment in the mid 90's. The schooling side of it was 8 weeks a year at university in blocks of 2 weeks at a time, for three years, in which is now considered as 'Advanced Certificate in Electronics'. I did extremely well, coming first every year out of 150 students. But admittedly the course was fairly basic compared in the scheme of things and didn't even touch on some of the concepts I am getting to grips with here.

It's only over the past twelve months that I have gotten back in to playing around with electronics, with the goal of finally building that computer from scratch.

So that's pretty much me in a nutshell, not a complete newbie, but happy to admit where I don't fully understand things. Hopefully you guys will find me approachable over time. I'm pretty easy to get along with.

[ThisWayUp]

Walking into this forum and asking a question is like walking up to Jimi Hendrix and asking him how he 'does that one solo thingy, the WEEDLY WEEDLY WEEEEEEEE!!!!' Sometimes I beat myself up for knowing almost nothing and being such a newb but then I remember most here have been doing this stuff, hands on, for longer than I've been alive and I'm no spring chicken.

[J64C]

Very true!

Feeling more confident with my project today. It's a mass of long wires and heaps of things connected all over the place.

Only running a simple routine, but have managed to dial up the frequency (doubling it each time) staring from a mere 1.5Hz. Amazingly it has been running stable for the past ten minutes at my target goal of 12.5 MHz!

Almost feels like if I can get away with that, with this mess, I'll be able to achieve anything.

I attempted to try my luck by doubling again to 25MHz, knowing full well I am way over the 14MHz rating and failed miserably. Which is totally fine by me. 12.5MHz is what I want.

[drogon]

J64C wrote:

Very true!

Feeling more confident with my project today. It's a mass of long wires and heaps of things connected all over the place.

Only running a simple routine, but have managed to dial up the frequency (doubling it each time) staring from a mere 1.5Hz. Amazingly it has been running stable for the past ten minutes at my target goal of 12.5 MHz!

Almost feels like if I can get away with that, with this mess, I'll be able to achieve anything.

I attempted to try my luck by doubling again to 25MHz, knowing full well I am way over the 14MHz rating and failed miserably. Which is totally fine by me. 12.5MHz is what I want.

Give it a go - you're not likely to damage anything... That's what I did with my Ruby boards - I started at 1Mhz and took it to 16Mhz on stripboard, then a double sided PCB. I've no real need to go faster as that's not my goal (and I know the memory is the bottleneck on the '816 board)

-Gordon

[plasmo]

J64C wrote:

I attempted to try my luck by doubling again to 25MHz, knowing full well I am way over the 14MHz rating and failed miserably. Which is totally fine by me. 12.5MHz is what I want.

Interested to see W65C816 runs at 25mhz, specifically 25.275mhz.
Bill

[BigDumbDinosaur]

plasmo wrote:

J64C wrote:

I attempted to try my luck by doubling again to 25MHz, knowing full well I am way over the 14MHz rating and failed miserably. Which is totally fine by me. 12.5MHz is what I want.

Interested to see W65C816 runs at 25mhz, specifically 25.275mhz.

If you extrapolate the FMAX vs VDD curve shown in the data sheet, it would seem 25 MHz is possible on five volts. I ran POC V1.2 at 20 MHz without any issues.

[J64C]

That’s the thing, the manuals seem inconsistent. When you look at the W65C02 manual it states, 14MHz at 5V. Then you look at the graph and it does show ~25MHz at 5V. Then even ~40MHz at approx 7V.

[GARTHWILSON]

J64C wrote:

That’s the thing, the manuals seem inconsistent. When you look at the W65C02 manual it states, 14MHz at 5V

That's the conservative guarantee, to do at least 14. It may (and does) go faster, but it's just not guaranteed to. Forum member "Windfall" has a 65816 running at 24MHz at 3.3V! That's three times the 8MHz it's guaranteed to do at 3.3V.

[BigDumbDinosaur]

J64C wrote:

That’s the thing, the manuals seem inconsistent. When you look at the W65C02 manual it states, 14MHz at 5V. Then you look at the graph and it does show ~25MHz at 5V. Then even ~40MHz at approx 7V.

Welcome to the wacky world of WDC documentation. Especially in their older data sheets, there are quite a few errors. Fortunately, their products are much better than the data sheets would lead you to believe.