About using Static RAM: the C16 expansion case

[eslapion]

Gentlemen,
...

Vaguely reminiscent of 2 famous lines from an old movie...

- I come in peace !
- You go in pieces!

Man, this dates back to 1990. Am I really that old ? Looks like I am...

[Gyro Gearloose]

I cleverly avoided the C16 RAM issue by buying a Plus 4. Boy am I smart. I wonder if one day I'll be able to put something useful instead of the built-in crap.

[eslapion]

I cleverly avoided the C16 RAM issue by buying a Plus 4. Boy am I smart. I wonder if one day I'll be able to put something useful instead of the built-in crap.

Saruman-64 and Saruman-TED are both ready for you. Since you have a Plus/4, I would suggest Saruman-TED with no switch.

[eslapion]

Yes, the problem is that: one approach can be right, yours one is surely wrong....

My approach, when something doesn't work the way I expect is to check every possibility and every possibly implicated signal... everyone of them.



Gotta love this guy...

I don't limit myself to the flimsy, sketchy junk from Commodore. The result is this:

The wire-wrap handmade version of Saruman-TED. It works perfectly well and it has attachment points for every single signal coming in and out of the TED. Like you would ever do this to properly study a Commodore computer or circuit. It's yours for $200US if you want a good inspection tool for TED computers. Fully tested and working.

Ya... I must be so wrong... j4ack455...

[MCes]

Yes, the problem is that: one approach can be right, yours one is surely wrong....

My approach, when something doesn't work the way I expect is to check every possibility and every possibly implicated signal... everyone of them.

Yes, everyone else but not the original datasheet...
And your technical ability on this is clear: SARUMAN-TED until christmas 2019 was 2 revisions of not working projects....

DSC03237.JPG
The wire-wrap handmade version of Saruman-TED. It works perfectly well and it has attachment points for every single signal coming in and out of the TED.(..)

It can be working because it is not your original design but the V1.4 "Christmas patched " version with the OR gate that ONLY on WRITE shorten the /CAS signal with PH0 CLOCK line...

Sometimes people lose the opportunities to be silent...

To speak to stones is more productive,
facts evidence is that your empiricism drove you to fail,
your vanity inhibit you to admit it, but if you are still working around "how to short the enabling of the RAM chip " this means that you know that your initial solution is wrong.

Do you think that your new schematics with trigger inverters (didn't have to be with XNOR?) will be working?
amaze us! realize it and public the results!
(it can't have a decent READ timing...)


I close with:
GOOD LUCK to you and to who believe in yours mumbles

[eslapion]

It can be working because it is not your original design but the V1.4 "Christmas patched " version with the OR gate that ONLY on WRITE shorten the /CAS signal with PH0 CLOCK line...

Well, unlike you, I learn from my mistakes... you still sell VIC-20 expansions that can wreck VIC-20 cart port connectors.

Your 'new and improved' surface mount version of your C16 expansion requires a socket added underneath!!

Do you think that your new schematics with trigger inverters (didn't have to be with XNOR?) will be working?
amaze us! realize it and public the results!
(it can't have a decent READ timing...)

If you think it can't have a decent read timing then you don't know how these components interact. I suggest you check using something like Microcap. https://www.spectrum-soft.com/demo.shtm

The double inverters version was tested and worked, The XNOR was tested and worked. The single OR version required fewer parts...

... still writing incomprehensible English!!

Anyways, it looks like you've made yourself quite a reputation.

Just got this e-mail:

There is a user called MCes on the Plus4World forum. I have noticed before that he is quite aggressive. He has developed some hardware for the C16/Plus4 and attacks anyone who he sees as a rival.

Hey! Looks like I'm a member of a select club!

[MCes]

Just got this e-mail:

There is a user called MCes on the Plus4World forum. I have noticed before that he is quite aggressive. He has developed some hardware for the C16/Plus4 and attacks anyone who he sees as a rival.

Hey! Looks like I'm a member of a select club!

Normally I am hated by who write technical bullshits because I have the background for unmask them....

I take this opportunity to congratulate you about your new club ...

Who know to be on the wrong part of the tecnical argument now is so desperate that is trying the personal attack.... it's only misery ....
I could answer on the same level, but I prefer to show a MY mail:

Hi (XX),
yes, i seen the payment.

Originally Posted by (XX)
"I could addvertise those in Facebook group"

I am an old-style man, and I will explain what....

In the same days that I was waiting for the PCBoards of this project Mr. (YY) shows on Facebook its "(ZZ)" that's an internal expansion with same functionality of mine (...).
I and (YY) had message contacts and I decided that I will not present my expansion on Facebook (where (YY) was starting before) but my project is available via Ebay, Amibay, and some technical forum.
I consider this as respect of others work (some others use an opposite comportment with me, but I'm happy to be different to some people...).
I use the money gained with this hobby to realize the next project, not for living.

So I invite you, on public facebook post, to not write about my expansion.
(...).

Thanks for comprension
(MCes)

Now is more clear which kind of person I am, and which kind of person he is.

And now that's enough,
the discussion is become sterile and I let, for who want, the opportunity to speak alone,
that for him is the only possibility to don't be contradicted.

GOOD LUCK

[orion70]

This topic is becoming just another fight over technical questions. Whoever wins or is right, is up to everyone's judgement. As for me, I'd lock it down.

[eslapion]

Given the opportunity to present my point without the verbal attacks, I'd be glad to post a video where I show a C16 working with an additional 64k of (static) RAM with things that supposedly shouldn't.

[MCes]

I take this opportunity to focus on the core:
"64KxC16" was developed studying the chips specs and then verified on the C16 for matching the WRITE and the READ time specs: the enabling /CAS was shortened only during the WRITE cycle making an ORing R/W with PH0 signal,
this guarantees that data from CPU is still valid when the WRITE activity will end (it's vital for the S-Ram writed data integrity).

Eslapion informed us that he based his project (SARUMAN-TAD V1.2) not on Commodore datas but on datas that he captured himself from own C16, his measures tell that on write cycle the DATAs from CPU are still available at /CAS rising edge.

Result:
64KxC16 was working from the first "alfa" version,
SARUMAN-TED without WRITE time limiting never worked,
the last version can work because was implemented a OR gate that limit the write time, as I always said (I and Commodore engineers...).

Why the measurements was wrong?
I have an idea....

This morning I organized a test about C16 bus timings, I triggered my oscilloscope on falling edge of PH0 that occurs only during a WRITE activity (CPU is driving the DATA bus..) and I read the trigger circuit delay: less or more 10nS

Than I tested Data0 line....

Data appear to be not corrupted also beyond the rising edge of /CAS signal...
So Eslapion had well measured but some unlucky C16 have different timings?

I observed something of strange....
so I made a little test: a resistor was placed from Data0 to ground for intercept a my doubt,
and this is the result.....

And voilà!
The CPU work as spec (or less too): At /CAS rising edge the CPU is not driving its data pins ( pins= high impedance) and the voltage remain on floating PCB traces (and leakage capacitance) until other devices will get the BUS, so on rising edge of /CAS a "floating" data will be captured.
Any kind of noise can destroy the information stored in a "not feeded" bus, also something that is from the cartridge connector...

Do I need to add anything else?
Oh yes:
GOOD LUCK!

[eslapion]

Data appear to be not corrupted also beyond the rising edge of /CAS signal...
So Eslapion had well measured but some unlucky C16 have different timings?

I observed something of strange....

There you go...

so I made a little test: a resistor was placed from Data0 to ground for intercept a my doubt,
and this is the result.....
...
And voilà!
The CPU work as spec (or less too): At /CAS rising edge the CPU is not driving its data pins ( pins= high impedance) and the voltage remain on floating PCB traces (and leakage capacitance) until other devices will get the BUS, so on rising edge of /CAS a "floating" data will be captured.
Any kind of noise can destroy the information stored in a "not feeded" bus, also something that is from the cartridge connector...

Do I need to add anything else?

Yeah but the threshold level for TTL/NMOS devices is 1.3V so the data is still valid. You're not indicating the value of your added resistor and you're not showing what happens when the value of D0 happens to be a logic 0. This brings the question: What impedance loading will render the data unreadable? Is this an impedance load you can reasonably find in a Commodore 8 bit computer ? I suspect not.

Sidenote: You still don't understand why GandALF had to be fitted with a 74HCT74 because you don't understand logic threshold levels... TTL/NMOS -> 1.3V and for CMOS 5V -> 2.5V big difference.

Oh yes:
GOOD LUCK!

Oh yes... IMMATURE!

Gee... I'd love to argue about technical stuff with you but 1. I can't even make sens of what you're writing because it's 50% gibberish 2. Enough of the insults and the personal attacks; be a damn adult or get a diaper change

[MCes]

The different versions of SARUMAN-TED show that you are a fake.

Better to be immature than paranoid,
better be direct than fake,
better understand than pretend to know,
better to be than to pretend to be.

You have removed any doubt to those who wondered why another technical forum kicked you out:
it is because a forum without Eslapion is better than a forum with Eslapion ...

Who has technical knowledge has understood which of the two is to be pitied,
I tried to stay on a hard but technically motivated path, your lack of intellectual honesty makes it useless.

So I close here: I have no other time to waste, I have to develop other projects...
Tonight I'm going to see an old black and white film, it's very informative.... (eng subtitled)

https://www.youtube.com/watch?v=ydsc0q-FMEo

I forgot ....
-good luck to you and those who believe you ....

[eslapion]

I observed something of strange....
so I made a little test: a resistor was placed from Data0 to ground for intercept a my doubt,
and this is the result.....

What is the value of the resistor ?

[Gyro Gearloose]

Guys, we're all about halfway to death at our age and this is what you chose to do with what's left of your mortal time?

[groepaz]

Play with a C-16? =)