semtex
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 3:02 am

I read at http://elinux.org/RPi_Hardware that the GPIO, JTAG, DSI and CSI interfaces will not have connectors fitted on the production RasPi boards.

I don"t mind the missing GPIO and JTAG headers because these can be easily added later. But I"m concerned about the connectors for the CSI and DSI interfaces. These enable cameras and external displays but will a hobbyist be able to source the correct connectors and, more importantly, actually solder them as they are surface mount connectors (unlike the GPIO and JTAG headers).

What was the rationale behind not including these connectors?

Thanks

Post edit by Gert: Yes there has been a lot of confusion about the CSI/DSI connectors being present or absent. Today (5-March-2012) I have been told that the CSI and DSI connectors ARE in place.  Excuse to semtex for post editing his entry but I am only trying avoid the potential of more confusion by answering his question here instead of somewhere on the end of page 2.

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Chromatix
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 3:08 am

My guess is that they are not so often useful, even compared to GPIO, and they are an extra expense to fit at the factory.  The DSI connector at least has no standard pinout to it, so a custom ribbon connector between it and whichever LCD would be needed anyway.  I don't know whether that's also true for CSI and camera modules.

Perhaps if the pinout/usefulness problems are solved somehow, probably by producing cables to a small number of standard peripheral types, a version with the connectors included will appear in future.

As for GPIO, IIRC that was left unpopulated deliberately because different hobbyists wanted the pins to point in different directions - up, down, sideways, you name it.  Easiest to solve by letting them solder it in themselves - easy since it's 1/10" through hole.
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nick.mccloud
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 9:07 am

semtex said:


What was the rationale behind not including these connectors?


Hitting the price point of $25/$35 dollars.

They can go back and do a more expensive version at a later date with these connectors on.

kasperl
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 9:16 am

Being surface mount is a bit of a pain to be honest, especially as there are people willing to make screens for the DSI interface. A custom ribbon is probably more easy to make than a custom connector. But the pinout for the DSI and CSI haven't been made public yet, have they? As long as that's the case, we can't use it anyway.

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Jongoleur
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 10:20 am

AFAIK (or understand, even)  The "interfaces" are there, its just that the board connectors haven't been populated. Its all down to cost.  A few pence here, a few pence there and it all adds up and BANG goes saxpence!

Sorry, I meant to say that every little added means that the board price will creep up and eventuall exceed the target for little useful gain... 

And "BANG went saxpence"?

http://bp0.blogger.com/_Cp2XFV.....pence3.jpg
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hippy
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 12:19 pm

semtex said:

I'm concerned about the connectors for the CSI and DSI interfaces. These enable cameras and external displays but will a hobbyist be able to source the correct connectors and, more importantly, actually solder them as they are surface mount connectors
Most hobbyists likely won't be able to solder the connectors on if they could source them.

I expect the Foundation's manufacturers will produce a version of the boards with one or both connectors fitted at slightly higher cost some time in the future.

mobeyduck
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 12:47 pm

The foundation has plans to make add-on boards/cards with a camera

And they also have plans to make/source a lcd, but every mode/type of screen needs different settings, drivers, connectors.

Since there isn't a screen with drivers ready to be used and the foundation having there hands full they don't have working screens and cant sell them to you. If there would be a connector on the board that doesn't fit it would suck if there isn't a connector they save a few penny's and you dont get pissed since your board isn't supported because of a lousy connector that doesn't fit.

tldr; the board is future proof

arm2
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 3:59 pm

The foundation has said the any particular model of camera fitted has to be calibrated which IIRC is more than two man weeks. They expect to offer a low and high spec camera supplied ready fitted at an unknow price later in the year.

So there is no pouint in them ever fitting the camera connector except if a camera is also supplied.

not fitting the screen connector is I presume a cost saving.

nullstring
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 4:06 pm

hippy said:


Most hobbyists likely won't be able to solder the connectors on if they could source them.

I expect the Foundation's manufacturers will produce a version of the boards with one or both connectors fitted at slightly higher cost some time in the future.





Why not? They don't look that hard to solder on from where I stand.

There are plenty of hobbyist projects elsewhere that require you to solder surface mount chips that are much harder than this.

hippy
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 4:48 pm

Perhaps you are right ...

http://www.raspberrypi.org/wp-.....front1.jpg

Not as fine pitched as I thought they were and pads on both sides of the connector are joined. I recalled it was the same pitch as the HDMI connector which looks to be 0.025" but apparently not!

Though it still is a quite fine pitch ( 0.05" it seems ) and getting behind the LAN socket with a soldering iron for DSI could be awkwrad. CSI looks easier.

I'd still venture most hobbyists won't have the tools or experience to make a clean job of it.

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jojopi
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 5:22 pm

hippy said:

Though it still is a quite fine pitch ( 0.05" it seems )
I believe the pitch is 1mm (0.039").  Personally I think the intention must have been to fit them, but it has still never been confirmed either way whether they are being fitted.


arm2
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 6:27 pm

jojopi said:


hippy said:


Though it still is a quite fine pitch ( 0.05" it seems )


I believe the pitch is 1mm (0.039").  Personally I think the intention must have been to fit them, but it has still never been confirmed either way whether they are being fitted.


I must have read at least six official posts saying that those two connectors, the JTAG pins and the GPIO pins will not be fitted to model A or B and no posts contradicting that.

Unfortunately this info is not in the FAQ and trying to search for it comes up with a myriad of multi-page topics.

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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 7:12 pm

arm2 said:


The foundation has said the any particular model of camera fitted has to be calibrated which IIRC is more than two man weeks. They expect to offer a low and high spec camera supplied ready fitted at an unknow price later in the year.

So there is no pouint in them ever fitting the camera connector except if a camera is also supplied.

not fitting the screen connector is I presume a cost saving.


Cameras need a lot of 'tuning' to make the images look right. In some cases (let's say the camera on the Nokia N8, regarded as the best until the Nokia 808 launches), this can take man-years. They also need drivers for the camera (and lens if fitted) to be written, and they take ages to tweak as well.
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Gert van Loo
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 7:13 pm

Hi guys,

Just my two cents/pennies worth. As far as I know it is not yet sure what the connector status is despite everything written about it.

For example the trial run of the beta boards had the GPIO connector mounted 'by accident' as the foundation forgot to omit it.

So I strongly suggest we wait what the production beta boards look like. I know Eben has some so I will ask him on Monday.

hippy
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 8:08 pm

Just to note that Farnell shows the board with connectors fitted. Of course that may not be reality. Did not check RS ...

http://uk.farnell.com/producti.....185-40.jpg

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Chromatix
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 8:20 pm

I haven't seen *anyone* with a photo of a production board - not even the Foundation themselves.  The only photos seem to be of the early prototypes, then various alpha and beta boards.

The early prototypes are very different from anything later.

The alpha board is somewhat larger than the beta and production boards, and has buttons on it.

The beta board has the oversized SD card slot (very visible in most photos), and is fitted with upward GPIO header and DSI and CSI connectors as standard.

The production board, as I understand it, will look similar to the beta board *except* that the GPIO, DSI and CSI headers will be missing, and the SD card slot will be much more compact.  Of course hobbyists might fit their own GPIO header, but the other differences are likely to persist.
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arm2
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Re: Rationale behind missing connectors? [RESOLVED]

Sun Mar 04, 2012 9:40 pm

hippy said:


Just to note that Farnell shows the board with connectors fitted. Of course that may not be reality. Did not check RS ...

http://uk.farnell.com/producti.....185-40.jpg



All beta boards had the extra connectors fitted, when they get some production boards hopefully they will update the photo's quickly.

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Gert van Loo
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 7:42 pm

Final word: spoke to Eben today. The boards WILL, DO, POSITIVELY, YES,  HAVE the DSI and CSI connectors in place.

Now the only problem left is the title of this post which will confuse anybody. So I leave this post open a short while longer but I will try to post-edit the top entry.

kasperl
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 9:42 pm

Woohoo! Here's one for the FAQ. Good news!

arm2
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 9:43 pm

Very good, interesting news.

How tall are the DSI and CSI connectors?

I need to check the clearance on my RTC board design.

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abishur
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 9:47 pm

based on the photos, they are shorter than the ethernet or usb ports
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arm2
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 10:11 pm

Eeeckkk Having read in more than one Admin posting/tweet that they weren't going to be fitted. I'll now have to rely on the being shorter than the Ethernet socket.

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abishur
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 10:20 pm

arm2 said:


Eeeckkk Having read in more than one Admin posting/tweet that they weren't going to be fitted. I'll now have to rely on the being shorter than the Ethernet socket.



but... that's what I said?
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semtex
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Re: Rationale behind missing connectors? [RESOLVED]

Mon Mar 05, 2012 11:14 pm

Final word: spoke to Eben today. The boards WILL, DO, POSITIVELY, YES,  HAVE the DSI and CSI connectors in place.

Now the only problem left is the title of this post which will confuse anybody. So I leave this post open a short while longer but I will try to post-edit the top entry.

This is great news. Thank you Gert... and no worries editing my original post. I was just about to do that when I noticed it was already done. Thanks again for the definitive answer.

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