Michael
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Re: Physical design

Sat Aug 13, 2011 10:13 am

Well I had guessed USB and Ethernet the wrong way around!
Where is SW1? [Edit: top side, in the same area as the SDcard reader on the underside]
JTAG is easy to identify. Gert, is there just the one JTAG interface on Broadcom - the one into the GPU? Thus this is the header you are proposing to delete?
Gert, are you saying that J4 is DSI or the currently unlabelled header immediately to the right of HDMI is DSI? If the former, what are the headers immediately to the left and right of HDMI?

Finally, what is the component immediately below the DC Jack? [Edit: Okay, its just a diode]

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Re: Physical design

Sat Aug 13, 2011 11:27 am

Quote from Michael on August 13, 2011, 11:13
Well I had guessed USB and Ethernet the wrong way around!
Where is SW1?
JTAG is easy to identify. Gert, is there just the one JTAG interface on Broadcom - the one into the GPU? Thus this is the header you are proposing to delete?
Gert, are you saying that J4 is DSI or the currently unlabelled header immediately to the right of HDMI is DSI? If the former, what are the headers immediately to the left and right of HDMI?
Finally, what is the component immediately below the DC Jack?


JTAG goes directly to the GPU. Arm debugging is done via USB/GDB I think, although there is some sneakyiness in there to make things work nicely.

The component below the DC jack in the picture is component video out.
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Michael
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Re: Physical design

Sat Aug 13, 2011 12:08 pm

Is there a picture?

[Edit: Gawddamnit, the picture is on the home page of the website. Why didn't anyone mention that in the forum? Right, off to read the article and look at the PCB pwrn!]

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Gert van Loo
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Re: Physical design

Sat Aug 13, 2011 12:16 pm

SW1 is the reset switch. I will re-define the DSI/CSI connector now as you look at the main picture: J12 is DSI, (left of HDMI in the picture) J13 is CSI. (right of HDMI in the picture) ARM JTAG is a function of the GPIO pins. GPU JTAG will become a Do-Not-Fit. We expect most ARM debugging to be done using the standard Linux debugging tools. JTAG is mostly needed for hardware bring up which we have already done.

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Re: Physical design

Sat Aug 13, 2011 1:04 pm

Is the GPU JTAG J5 or J9? What is the other one?

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Re: Physical design

Sat Aug 13, 2011 4:41 pm

Quote from Gert van Loo on August 13, 2011, 09:15

So GPIO, CSI and DSI will probably all change. The challenge is to keep cost done but still allow somebody with crude solder equipment access to the ports. After all the main purpose of the organization is the education of computer skills (which to me includes hardware) all over the world. That is also the reason why we use full size connectors. Yes, we can go micro USB, micro SD and micro HDMI. But equipment to connect to that is not as widely available as the full size ones. You will notice that all connectors are through hole: a bit more expensive but a lot more robust. All external connectors have ESD protection (But we are still looking for smaller and .cheaper ESD parts.) The used audio 3.5mm plug is way too expensive, but the only one available in the design library at the time. And I knew you guys could not wait another three weeks to get all the right parts in the library.

(which to me includes hardware) That is very true. Our kids live in a hardware skills vacuum, they are consumers, if their friend has it they have to have it too. So they BUY it. Customizing to them is adding UV and color changing lights. Designing a device that they have put a little brain strain into to getting it to work will be good for them. I had to learn through proprietary expansion, ISA, EISA, VESA, PCI and on. I forgot a couple of video ones in there some place, oh yeah MCA and AGP.

It is hard to believe that something that is so ubiquitous as a 3.5mm sound jack is so expensive. Is it the demand that causes it?

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Re: Physical design

Sat Aug 13, 2011 5:14 pm

that is so true lobo, those kids today know nothing about hardware or how it works..
well most of them.. there are always exeptions - hopefully.

apart from the model a im going to order for my uav project, i will also order a model b which will loose all its connectors since i dont need them. im only buying the model b cos it has more memory.

but it is nice to know how the released board will look like when they ship it.
the alpha board gives a good example how flat the raspi can be without the connectors.
i estimated the arm with the pop memory to be more bulky but its realy flat..

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Re: Physical design

Sat Aug 13, 2011 6:25 pm

With the design of these boards it should be possible to remove all of the connectors without damaging the board. In a UAV such as you are building any weight you can remove is a plus. A bigger consideration is hard wiring will be much more robust than than coonectors. Space is also a premium. The tallest things left on the board will be the cans (capacitors).
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Re: Physical design

Sat Aug 13, 2011 6:43 pm

right.
but weight is not such an issue for my uav.. but i have to reduce the height to make the electronics chamber as flat as possible.

it would be nice if the raspi team would provide some kind of a naked raspi without the connectors and maybe only route the possible connections to a single pinstrip.. would save some money i think..
for schools or whoever needs it, they could provide a adapter cable which fitts onto the pinstrip and provides on the other end all connections.. but that again would involve more money to spend..
ahh.. its hard to make it right for everyone ;-)

Cafe
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Re: Physical design

Sun Aug 14, 2011 4:37 am

Quote from AmyS3 on August 13, 2011, 19:43
...it would be nice if the raspi team would provide some kind of a naked raspi without the connectors and maybe only route the possible connections to a single pinstrip.. would save some money i think..
for schools or whoever needs it, they could provide a adapter cable which fitts onto the pinstrip and provides on the other end all connections.. but that again would involve more money to spend..
ahh.. its hard to make it right for everyone ;-)

A Raspi with port connections but no connectors and an optional add on docking cable/station would be great. Alas, as you say, the add on might cost much more than the cost of shipping with the connectors attached, and the number of people wanting the Raspi without connectors might be, relatively, too small.

I guess, we will be fine as long as we can remove/replace the connectors ourselves without risking damage to the board.

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Re: Physical design

Sun Aug 14, 2011 4:47 am

I would love it if on Model B, the USB connectors weren't stacked vertically, but I assume they are stacked that way due to space constraints and that the combined height doesn't exceed the height of the RJ45 jack.

If horizontal space isn't a constraint, it would be nice to lay the two USB ports next to each other (with space between them to accommodate the width of a USB stick). With this layout, in applications that don't need RJ45, the enclosure can potentially be thinner, probably limited by the height of capacitors on the board.

A thin enclosure can be appealing when the Raspi is used with a touch display and a USB wifi adapter. (The alternative is Model A, but it doesn't have enough memory and it won't leave a spare USB port.)

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Re: Physical design

Sun Aug 14, 2011 5:43 am

Going to side by side USB ports will not do you much good on a model B the ethernet is just as tall. A model A is going to be the height of the cans (capacitors) antway. of course if you are good at desoldering you could remove the RJ45 and the USB connectors and run wires to the board instead.
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Cafe
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Re: Physical design

Sun Aug 14, 2011 5:56 am

Quote from Lob0426 on August 14, 2011, 06:43
Going to side by side USB ports will not do you much good on a model B the ethernet is just as tall.

Of course, thin enclosure is possible with horizontal USB placement only if we ourselves remove the RJ45. BTW, the vertical stacking doesn't help even if we remove the RJ45. So, it is better to place the USB ports horizontally, if at all possible.

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Re: Physical design

Sun Aug 14, 2011 8:12 am

The connectors are through hole I believe, so easier to dismount than surface mount (although even that's relatively easy - ever tried to change a games slot in a Nintendo DS?). Running out to remote connectors shouldn't be too horrendous, if you want a really thin client....
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Re: Physical design

Sun Aug 14, 2011 4:29 pm

I may have to do this to fit everything into a router case. I am trying to avoid it as I really do not want murder a RasPi in pursuit of a ridiculously small router/computer. It may have to be done though. Anyone have some desoldering braid? lol
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Giles Read
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Re: Physical design

Tue Aug 16, 2011 12:49 pm

I would like to see a port layout that allows the RasPi to operate in a minimum (yet common) configuration with connectors on just one edge. Otherwise, the device footprint becomes huge, once you take into account the cables you're plugging in.

For me, the ideal would be something like

Long side - power, HDMI, USB, [Ethernet, if space]
Short side - SD card
Short side - Ethernet, audio, RCA video
Remaining long side - nothing!

This would leave one side that was always cable-free and, in a standalone configuration, cables emerging only from one (long) side.

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Re: Physical design

Tue Aug 16, 2011 5:07 pm

See, that's interesting. My preference is for a long, thin PCB with HDMI on one short side, Ethernet on the other short side and SD card on one long side near one end. I have no preference for USB and analogue. You can't please all the people all the time!

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Re: Physical design

Tue Aug 16, 2011 10:06 pm

I agree with you Micheal except for the USB. Reduce it to mini USB, at least one, also on one of the ends. I always like to have the ability to work a device as "headed". PS2 is just too large and too inflexible. No sound for you huh!
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No1
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Re: Physical design

Fri Aug 26, 2011 7:20 pm

You could just drop it in an Altoids type tin, though you might need to make your own to make room for the ports and maybe make it a little bigger.

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Re: Physical design

Fri Aug 26, 2011 7:47 pm

Quote from Lob0426 on August 8, 2011, 00:15
OMG here we go with the aluma-wallet cases lol. "Carry your credit cards and your computer". Keep them safe from being read at a distance, the new identity theft! Lol. Don't forget to throw in a few matchstick boxes as well. Just remember that thieves very rarely steal plain Jane keyboards, that's where I am going to hide mine! "Super Mouse, the mouse with it's own built-in computer". There we go you got me started now!

Have you considored the movement virbration damage in your super mouse. The amouunt a mouse gets abused, I would not want my computer in there.

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Re: Physical design

Fri Aug 26, 2011 8:22 pm

Quote from Giles Read on August 16, 2011, 13:49
I would like to see a port layout that allows the RasPi to operate in a minimum (yet common) configuration with connectors on just one edge. Otherwise, the device footprint becomes huge, once you take into account the cables you're plugging in.

For me, the ideal would be something like

Long side - power, HDMI, USB, [Ethernet, if space]
Short side - SD card
Short side - Ethernet, audio, RCA video
Remaining long side - nothing!

This would leave one side that was always cable-free and, in a standalone configuration, cables emerging only from one (long) side.



Long side - HDMI, USB, AUDIO
Short side - POWER ,SD card
Short side - Ethernet, RCA video
Remaining long side - Power LEDs

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Re: Physical design

Fri Aug 26, 2011 9:52 pm

Lol. It can handle it, it is the supermouse.
I don't think vibration would do it in before the video cable decided to give up. You can handle the vibration through proper mounting. I can not figure out how to protect the cable and what about wire breakage. Those cables cost as much as the RasPi.
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rmike
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Re: Physical design

Thu Sep 01, 2011 8:12 pm

Hi,
it is probably to late anyway for this suggestion, but my wish would be to have:

* LAN and USB on one short side
* power, HDMI, Video, Audio on the other short side
* all through hole pin headers (not assembled) for SPI etc. on the long sides directly at the pcb edge (no headers in the middle of the pcb)
* all these headers aligned in 1/10 inch standard grid to be able to place the raspi in regular 1/10 inch grid protoboards
* headers grouped in function blocks and separated (serial port: 4 pins [RX,TX,3V3,GND], free space, SPI: 6 pins with power, free space, I2C: 4 pins with power, free space, etc.)

That would make it easier for people (students) to experiment and to connect to other electronics.

Michael

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Re: Physical design

Mon Sep 05, 2011 9:13 pm

Sounds like there's a future for a third model - Mod "C" would be a Mod "B" sans all connectors and a couple of pin headers for all power and I/O use. Only the reset switch and SD card socket to remain. Most educational uses would be well served with Mod "B"s and "A"s - and the "experimenter" would find the Mod "C" the near perfect slim fit for their super mice, etc. And someone will create, and offer, a daughter board with all the connectors on it to snap onto the Mod "C"...

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Re: Physical design

Mon Sep 05, 2011 11:27 pm

Mod "C" like an Arduino board with expansion shields for video, audio in/out , stepper motor driver etc, etc

Or make it so that it uses the numerous arduino shields already available?

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