The tale of the cases


I have cancel my pre-order but still interested on the project. Maybe I'll buy one when you update the CPU (if it happen, ofc).

Anyway, my condolences for the family. This kind of news hurts me for days.
 
Or because the Greeks, Portuguese, Italians and others take the entire month of August off, have poor services, shoddy workmanship, plenty of vacation, retire early with full pensions, and their stores don't even open until 11am.

In a world of scarce resources something has to give... In the Greeks case, it was their financial stability.
 
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EvilDragon said:
Thursday

I think I mentioned that the new company has a pretty awesome material mixture (that is about 5x as strong as other plastic materials).
They produced some samples for us on Thursday (as they had a production running that used that material).
As they don't have the Pyra moulds yet, they used some of ours. So I'll probably receive the most sturdy SNES / N64 / NES or MegadDrive cartridge shell of all time!

My contact plans to pick those up on Monday and will then ship them to me. Hopefully with the new Pyra case samples as well.. but we'll see.
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Please get sure that the carbon fiber within the plastic don't affect W-Lan, Bluetooth and / or 3G/4G
It would be bad if the Pyra gets a nearly indestructible shell but no wireless conection.
 
Bernd said:
Please get sure that the carbon fiber within the plastic don't affect W-Lan, Bluetooth and / or 3G/4G
It would be bad if the Pyra gets a nearly indestructible shell but no wireless conection.
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pseudo science guesswork. there is no proof of this. not tests no data. you will get far more interference from everything else that is on the 2.4 and 5 GHz bands.
 
spud42 said:
pseudo science guesswork. there is no proof of this. not tests no data. you will get far more interference from everything else that is on the 2.4 and 5 GHz bands.
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One could say the same as you do.
You too have no tests and no data so it's a valid request to have the new plastic tested on wifi compatibility.
It has been mentioned, that it most likely won't interfere, but better safe now than sorry later.
 
EvilDragon said:
Some 4GB RAM news

We're now 99% sure that the issue with the RAM is a too high voltage drop on our PCB, which means it needs some improved vias and ground plane.
.
Click to expand...

The same voltage drop that prevent the CPU from running with high clockrate? And where it turned out that it was a wrong setting?
Voltage drop for pcb traces that are only a few millimeters long is COMPLETE BS! If i read the mailing list, i am now 99% sure that you have no clue what causes this issue.

EvilDragon said:
This is what tests have shown
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What you do is not testing. It is called "playing around". With a test, you make predictions for the result before you do it. Not afterwards trying to explain and interpret what you have experienced.

EvilDragon said:
Well, I did expect a bit of chaos... but seriously, now I REALLY can understand why the country has financial issues!
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If the rest of the world takes you as an example for german product development, then we are f*ed.
 
Magic Sam said:
Hi all,

@Swordfish II : here's a wikipedia article about retirement in Europe:

https://en.wikipedia.org/wiki/Retirement_in_Europe

Cheers, Magic Sam

P.S.: the only two Greek people I know are astrophysicists... ;)
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Notice how the Greek and other retirement age were established/changed during the start of their financial crisis (so Germany would bail them and the Euro out) often Greeks sought early retirement at 45.

https://www.google.com/amp/amp.dail...simple-reasons-greece-is-imploding-right-now/
 
Zwerg01 said:
The same voltage drop that prevent the CPU from running with high clockrate? And where it turned out that it was a wrong setting?
Voltage drop for pcb traces that are only a few millimeters long is COMPLETE BS! If i read the mailing list, i am now 99% sure that you have no clue what causes this issue.
Click to expand...

Let's look at the voltages that ED has already mentioned

EvilDragon said:
Tony's Pyra works with 4GB RAM, if he powers it with at least 1.39V or if he disables DLL (then it also works with 1.35V)
Click to expand...

So, the voltage drop in this case is 0.04V or, 40mV. This is a very tiny voltage drop. Now, without knowing the current draw of the soc and ram we can't know what the resistance is, but, let's assume the soc and ram draw 600 mA, (anybody who knows the real number, feel free to chime in.) We can calculate the resistance using ohms law. Which plugging in the numbers we have gives us 40mV=500mA*R. This gives us 66.7 milliohms. That's a very tiny resistance, and considering how thin the traces can be, that's not an unreasonable number.

Plus, considering the voltage is supposed to be 1.35V, if there's a 40mV drop, then that means the voltage is 3% away from where it needs to be. Now, I haven't read the datasheet, but if I had to guess, I'd say the voltage supply probably needs to be within 1%
 
I sympathise with the designers over the memory issues - modern memory interfaces are both very fast and very configurable, both of which are good until you start debugging... The voltage drop mentioned is not so much a DC voltage drop (which won't be significant at the trace length and current) but an AC issue at the switching frequencies of the memory and interface. For these it's the AC impedance of the supply (which also depends on decoupling and reference planes) rather than just the DC resistance of the trace that matters. Have a look at PDN design, it's a topic in itself.

Once I spent several days debugging the A64 memory interface including extensive hacking of the FSBL, only to find I'd made a mistake on the BOM and speced the Zq resistors as 240k ohm instead of 240ohm.

PS: to reintroduce myself, I originally backed the Pandora when it was first announced but I was 11 at the time - it was an incredible device for an 11yo with a DS - but my parents made me pull out when card payments were cancelled for fear of the company going bust (in retrospect you can't entirely blame them). I've now decided to preorder a Pyra as I still want a device like this, also tempted by a second hand Pandora for the satisfaction of finally getting one.
 
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The RAM chip works from 1.28V to 1.45V under all specified circumstances. So your voltage drop has to be around 110mV. And this has to be on every motherboard.

40mV=500mA*R. This gives us 66.7 milliohms
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Your calculator must be broken. For me it gives 80mOhms.

With 110mV it gives us 220mOhms.

And with the fakt, that the chip only draws around 255mA on one line you can double this value to 440mOhms. So as i told you. Complete BS!

daveshah said:
I sympathise with the designers over the memory issues - modern memory interfaces are both very fast and very configurable, both of which are good until you start debugging... The voltage drop mentioned is not so much a Dc voltage drop (which won't be significant at the trace length and current) but an AC issue at the switching frequencies of the memory and interface. For these it's the AC impedance of the supply (which also depends on decoupling and reference planes) rather than just the Dc resistance of the trace that matters. Have a look at PDN design, it's a topic in itself.
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What will it recive? A digital half? Something between 0 and 1? The band between reception and no [URL='https://dict.leo.org/englisch-deutsch/reception']reception is very small. So why does it work for 2Gb?[/URL] As an example you mention a problem where you were three to the power of ten away from the design guide? SRSLY?
 
@Zwerg01

Yes, you are right, I miss typed my number.

You're looking at just the RAM, whereas both the ram and the soc need to be viewed together. If they're sharing the same power rail, they will affect each other very much

Also, Daveshah is correct. We're trying to analyze this from a purely DC perspective, where in reality we have a complex system of AC and DC, but I'm sure you know all about this, since it sounds like you've obviously designed your own system system with a soc from the ground up. Since you clearly know more than all of us here on what's wrong, why not suggest a solution?
 
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