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GPIO Access

Is there any way to have access to some GPIO pins so users could gain access and have a breadboard to build/program simple circuits?


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 I have an idea to create a GPIO breakout board. I have sent them an e-mail asking which pins they are using. Their answer was that information will be available soon.

This is very important.  It seems like even their own CEED Universe software assumes the user will be able to access GPIO pins.

Support told me that if you disconnect the GPIO cable, things will still work, except some features that rely on it like screen brightness control, battery status reporting, and a few others.

 


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Agreed. If this is to be an educational tool it must enable access. Otherwise, why not just get a Chromebook. BTW, I always get a communications error with the cable from the GPIO when I query.


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There seems to be a considerable silence about this from pi-top management. In particular, how is it proposed to connect HAT modules? Looks impossible without hardware modification.


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It looks as though there is a 2mm pitch 17x2 connector on the underside of the Hub board that an accessory board with a right-angled header could plug into. The accessory board would then be mounted onto the pi-top rail arrangement.


Perhaps Pi-Top plan to make such an accessory board that will replicate the HAT connections?



All you need to do is disconnect the 40 pin connector connected to the GPIO pins. If you do the GPIO is exposed but the volume up/down and screen brightness up/down keys don't work. A small price to pay to have the GPIO.

 

I forgot to mention if you disconnect this cable shutdown becomes a two step process.
First you go through the normal shutdown procedure.
The Wifi light will blink a few times then go off.
Next the green light on the RPi board will blink a few times and then go out.
At this time it is safe to hold the on/off switch down for a couple of seconds to kill the power.

 

The pi-topProto board shown in the blog  looks like the answer to the GPIO problem. Question is will it fit the original pi-top without the magnetic strips. Question 2 is how and when can we get these boards?

So, a year later and they are still shipping the pi-top without any kind of access to the GPIO. I'd love to learn of how any of you may have found a way to do it without also disconnecting the 40 pin cable from the other board. Like some kind of low profile 40 pin breakout that would still allow the smoked plastic cover to slide into place.

 

Look at the pi-topPROTO board

Sorry if I am missing something obvious but when I disconnect the 40 pin connector to get access to the GPIO pins, what powers the Pi?

It appears to derive power via the USB cable that connects between the power board and the Pi itself. I know it will work this way, just be aware you are going to lose a few features as mentioned above.

I got one of the PROTO boards and installed it, so I am now using the cloned GPIO pins of the PROTO board for connecting a GPIO Extension Board T connector to a breadboard. One thing about doing that, it seems the Pi-top is using some of the GPIO pins itself. I am still trying to determine which ones. But when I run a project that uses GPIO-0, there is a message which pops up in the Python Shell and states that "This channel is already in use, continuing anyway". For simply flashing an LED this doesn't seem to be a problem, but I have to wonder if I get into defining the other GPIO pins whether some conflict may occur that interferes with the operation of the Pi-Top?

If anyone can tell me which GPIO pins the Pi-Top needs for its own uses, I can avoid them while doing other experimental projects. Since the Pi board does seem to run OK without the power board's GPIO connector, I have to hope that very few GPIO pins would be seen as channels already in use when that connector is connected to the Pi.
The following things are controlled using gpio pins on the CEED and the laptop: spi (brightness, screen off). i2c (speaker filters and loudness). Laptop only: i2c (battery). The hub controller does remember the last brightness/screen off settings. It is therefore possible to use the pi-top without any gpio connection, if the last brightness value was high enough. If you look at github.com/rricharz/pi-gpio-display you can use all red pins.

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Thank you Rene! Looking at that diagram, I see that pins 7,29, and 31 are bright red. There are 14 other pins that are a shade of dark red or brown, as I see them. Did you mean I could use all 17 of these pins, or just the bright red ones?

 

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