OK, new idea. (UZEBOX Stamp?)

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Tue Sep 02, 2008 7:28 am

CompMan wrote:Will it fit in a standard breadboard?
Yep, it should. It's just standard 0.1" pin spacing with the rows 0.6" apart. (same as a dip socket)

-Clay

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Tue Sep 02, 2008 7:38 am

uze6666 wrote:About the Micro SD, a few mentioned the potential lack of SPI mode. I would not be concerned since two of the big makers supports it: Sandisk and Kingston (See Clay's last picture).
Agreed-- I don't think that'll be much of a problem. If any other manufacturer's are making/start making microSD cards it would actually be more effort for them to strip out the SPI support from their NAND controller than to just leave it in... So I suspect they will likely all have SPI support by default.

If someone just doesn't want to (or can't) use microSD for whatever reason, then you can always have a full sized SD card on the baseboard since the necessary signals all go to the pins. You could probably have both... Use one of the 'free' GPIO's for the card select on a second full-sized SD socket even.

At this point I've only ever seen Sandisk and Kingston microSD cards. (They're actually a little tricky to manufacture compared to a regular SD card which pretty much anyone can get a controller and NAND die and whip up a working board.)

-Clay

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Tue Sep 02, 2008 10:14 pm

I finished the Stamp layout and got all the DFM checks and everything done. I'll sit on it for another day until my sample parts arrive (to check form/fit), then place an order for a small batch of samples to see what all works.

This is the correctly rotated view with silkscreen. (If you don't want me to put UZEBOX on it, just let me know, Uze.) I put a legend there for either the 644 or 1284 as an option. (Basically check the box to tell them apart after assembly if we every use both at once.)

Image

For now I'm leaving the ISP header on there, but maybe we'll drop it for the production spin? (I could put down an optional audio output filter/volume control there instead maybe...)

-Clay

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Re: OK, new idea. (UZEBOX Stamp?)

Post by uze6666 » Wed Sep 03, 2008 1:04 am

For now I'm leaving the ISP header on there, but maybe we'll drop it for the production spin? (I could put down an optional audio output filter/volume control there instead maybe...)
Thinking about it, if used standalone, we need to wire it for power anyways. A few more wires for the ISP wouldn't bother much IMHO. Since the goal was to put all the "complex stuff" on the stamp, I'd say that there's much more value in having a sound filter/op-amp there than the ISP socket if there's no more room.

I'd be curious to hear what others have to say about that. But I agree it should be removed for prod.
If you don't want me to put UZEBOX on it, just let me know
On the contrary, it's pretty cool to see it there. If you can just put a small "tm" after it (I reserved the TM), consider this an "official written permission" ;) .

Best regards and congratulations for this amazing work.

Uze

ps: Are you planning do produce a baseboard around the same time? I guess after we settled that joystick connector issue...

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Re: OK, new idea. (UZEBOX Stamp?)

Post by uze6666 » Wed Sep 03, 2008 1:53 am

Btw, did you use a pin for the Micro SD slave select? I'm trying to allocate pin and right now, the most obvious would be PB4 (SPI SS). Also I'm wondering: if putting a regular SD on the baseboard, why not make them mutually exclusive? That would take up only one SS pin for the SD function. What's the risk of both were plugged simultaneously? Is there some sort of line contention protection on the SD cards?

Uze

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Wed Sep 03, 2008 3:10 am

uze6666 wrote:Thinking about it, if used standalone, we need to wire it for power anyways. A few more wires for the ISP wouldn't bother much IMHO. Since the goal was to put all the "complex stuff" on the stamp, I'd say that there's much more value in having a sound filter/op-amp there than the ISP socket if there's no more room.
I talked myself in and out of it about three times. ;-) On the one hand, not having the filter allow people to use that pin as GPIO if they don't want/need sound. On the other hand, it means you can't use the 'stamp' as a stand alone computer and have filtered sound. I finally decided it would be more flexible to leave it up to the baseboard since we could shift the cost of the filter to that instead (rather than burden *every* stamp with it) and it would allow more options for filters-- like 'none', 'cheap' (RC), 'good' (active opamp), 'best' (programmable w/ volume control)...

But... if we dropped the ISP header I could definitely fit something there. The downside is that to do the 'good' one it'd be more expensive because I'd likely need an MSOP or SOT-23 sized opamp to fit. (vs. SO-8's which I have tons of)

I did kinda like the ISP header since you can inject power there all in one connector... So if you had a STK500 or something plugged in it would just work. I'm not married to the idea one way or the other.
I'd be curious to hear what others have to say about that. But I agree it should be removed for prod.
Same here... Open for comments.
On the contrary, it's pretty cool to see it there. If you can just put a small "tm" after it (I reserved the TM), consider this an "official written permission" ;) .
Cool, I'll see what I can do. I can't promise the TM will show up very well though! (the picture is deceiving... the text is only 10mil wide lines and the smallest I can do is 6 mil, so it'll be pretty small as a superscript!) :lol:
Best regards and congratulations for this amazing work.
Thanks-- but thank you for coming up with something worthy of doing some custom hardware for! ;-)
ps: Are you planning do produce a baseboard around the same time? I guess after we settled that joystick connector issue...
Yep, I was eager to try a few. An "kitchen sink" version with MIDI/serial/joysticks/expansion headers/etc., then maybe a "game" one (joysticks, A/V only), then maybe a 'micro' one. (like buy one of those "tv game" joypads and make a compatible PCB for it that includes the stamp onboard.) :D

-Clay

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Wed Sep 03, 2008 3:53 am

uze6666 wrote:Btw, did you use a pin for the Micro SD slave select? I'm trying to allocate pin and right now, the most obvious would be PB4 (SPI SS). Also I'm wondering: if putting a regular SD on the baseboard, why not make them mutually exclusive? That would take up only one SS pin for the SD function. What's the risk of both were plugged simultaneously? Is there some sort of line contention protection on the SD cards?
What I did was use PD6 for the 'card select'. There was really only three reasons for that-- 1) a commercial SD/CF FAT library I bought for another project used it, and 2) I went ahead and called the rest of PD3-PD5 "SPI_CSx" for a total of four. 3) It just so happened that PortD routed on the PCB much better because of its proximity to the ISP header which I had to run the SPI signals out to anyway... The resulting pinout is a little "different". It's a hardware engineer pinout. :oops: (AKA, I placed pins based on where I could get the best routing channels and best power and ground into the video section, so the pinout jumps around a little bit.)

Image

Here's the schematic in PDF form:

http://www.embeddedengineeringllc.com/U ... mp_1.0.pdf

Risk-wise to SD, I don't think there's *too* much. The SPI is a multidrop bus *anyway*, so that's fine. If two cards were selected at the same time their data out pins *would* fight with each other, but the clock period is so small I doubt there'd be any damage to the cards. The timing differences between two cards would probably be enough to garble any transactions and it would probably be pretty obvious pretty fast that something's "not quite right".

I think that the main upside to sharing a single pin is that a baseboard can have a regular SD socket on it and it can be used as the "primary" SD for development and what have you (just don't put a card in the micro SD on the stamp). Standard SD is a lot easier to grab onto and will probably stand up to lots more insertion/removal cycles than microSD if you're doing hundreds of swaps testing/debugging/etc. (Harder to lose on the carpet too.) ;-)

-Clay

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Re: OK, new idea. (UZEBOX Stamp?)

Post by uze6666 » Wed Sep 03, 2008 4:18 am

Fair enough for PD6! Great to see that universal joystick interface laid down. I will just have to upgrade the API to support the new kinds. The pins you marked as reserved in your schematic are currently NC?

Oh and I didn't register the trademark since its not required (common law trademark). :)

Cheers,

Uze

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Wed Sep 03, 2008 4:33 am

uze6666 wrote:Fair enough for PD6! Great to see that universal joystick interface laid down. I will just have to upgrade the API to support the new kinds. The pins you marked as reserved in your schematic are currently NC?
The pins on the 'DIP' module marked as reserved are loaded (there's a pin there), but they don't go anywhere. I didn't have any other pins on the AVR that *had* to go out and I didn't really want to eat up all the pins just because they're there without thinking about it more...

One thing that occurred to me was to bring up RGB... That way we could do SCART (or arcade game monitors). The problem was that right now I have sort of a left-> right flow on the board with the left being digital and right being analog-- if I tried to use those free pins I'd have to run some analog back under the digital section. It might be OK, but I didn't want to risk it on the first prototypes. It would also mean sacrificing some ground plane, so again, just for signal integrity purposes I thought it best to err on the side of caution for now.
Oh and I didn't register the trademark since its not required (common law trademark).
Ahhh, gotcha. I immediately think of all the 'official' patent/trademark stuff that the corporate types here immediately do. ;-)

-Clay

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Re: OK, new idea. (UZEBOX Stamp?)

Post by havok1919 » Thu Sep 04, 2008 1:37 am

Got my parts today! (Except for the AD723.) The AVR footprint looks good, so I think I'll just pull the trigger and order boards. (Getting antsy.) :D

-Clay

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