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by sparkyPi
Fri Dec 18, 2015 4:14 am
Forum: Official Foundation Display
Topic: Developing GUI application to run on 7" RPi DSI Display
Replies: 24
Views: 10899

Re: Developing GUI application to run on 7" RPi DSI Display

@ AndyD , topguy : Thanks for the brainstorming and contributions here! It's beyond my expertise and time to dig deeper into this, but it seems like we at least identified a path forward that would be worth trying by someone with sufficient skills: patching Qt5 to use the DispmanX/EGLFS plugin and m...
by sparkyPi
Wed Dec 16, 2015 10:51 pm
Forum: Official Foundation Display
Topic: Developing GUI application to run on 7" RPi DSI Display
Replies: 24
Views: 10899

Re: Developing GUI application to run on 7" RPi DSI Display

- The best way would be if someone patched the standard xserver to support options about which screen to open on, similar to how Kivy does it. It doesnt need to be accelerated just a framebuffer to render to. Then you could just start two X-servers, one for each screen. - Or a dispmanx based VNC cl...
by sparkyPi
Wed Dec 16, 2015 10:45 pm
Forum: Official Foundation Display
Topic: Developing GUI application to run on 7" RPi DSI Display
Replies: 24
Views: 10899

Re: Developing GUI application to run on 7" RPi DSI Display

To be honest I a not sure, but my gut feeling is that it would be a reasonable amount of work. Perhaps a better way to approach the problem would be to find a (reasonably simple) GUI framework that is already targeted to the Linux frame buffer and make a DispmanX backend. The DispmanX API has some ...
by sparkyPi
Wed Dec 16, 2015 9:30 pm
Forum: Official Foundation Display
Topic: Developing GUI application to run on 7" RPi DSI Display
Replies: 24
Views: 10899

Re: Developing GUI application to run on 7" RPi DSI Display

Unfortunately, no it isn't possible. It would work if there was a DispmanX or a Open GLES backend for GTK, but I don't believe one exists. Thanks, AndyD for the quick and clear answer -- very helpful to know. If DispmaxX or Open GLES is mandatory, how would one go about creating a basic GUI (from s...
by sparkyPi
Wed Dec 16, 2015 8:11 pm
Forum: Official Foundation Display
Topic: Developing GUI application to run on 7" RPi DSI Display
Replies: 24
Views: 10899

Developing GUI application to run on 7" RPi DSI Display

Hi folks, I've seen and read a few threads on the topic of dual display usage but am still searching for direction regarding running a GUI application on the 7" LCD while the HDMI output is configured as default. Background: We know it's possible (see here and here ) to attach HDMI and official 7" D...
by sparkyPi
Tue Oct 13, 2015 6:35 pm
Forum: C/C++
Topic: wiringPi: I2C 16-bit transfers (little endian/big endian)
Replies: 4
Views: 4359

Re: wiringPi: I2C 16-bit transfers (little endian/big endian

The device determines the byte order. I don't remember anything in the I2C spec which mentions the byte order (if there is such a statement it is ignored by devices I use). Hi Joan, I agree --- it's up to I2C slave devices to define in their datasheet the order in which data is expected to be recei...
by sparkyPi
Tue Oct 13, 2015 4:59 pm
Forum: C/C++
Topic: wiringPi: I2C 16-bit transfers (little endian/big endian)
Replies: 4
Views: 4359

Re: wiringPi: I2C 16-bit transfers (little endian/big endian

Hi Gordon, Thanks very much for your reply to my post. I appreciate your comments --- I'm no longer worried of doing something wrong, particularly if it is the first time it is being done! :D I'm glad I could provide some feedback on your library after all this time. Following your note on wrapping ...
by sparkyPi
Sat Oct 10, 2015 7:28 pm
Forum: C/C++
Topic: wiringPi: I2C 16-bit transfers (little endian/big endian)
Replies: 4
Views: 4359

wiringPi: I2C 16-bit transfers (little endian/big endian)

Hi Gordon ( wiringPi developer) and community, I'm on a roll with wiringPi posts...this is the last one! I have a question regarding the endian-ness of 16-bit transfers when using I2C library functions in wiringPi. (I think the issue may be the reason people have trouble using I2C library of wiringP...
by sparkyPi
Sat Oct 10, 2015 6:54 pm
Forum: C/C++
Topic: wiringPi: Request support for additional SPI mode bits
Replies: 0
Views: 2189

wiringPi: Request support for additional SPI mode bits

Dear Gordon ( wiringPi developer) and community, I hope it's okay to post a mini "enhancement request" to wiringPi here --- I see Gordon found my other post related to wiringPi so I thought posting here might be helpful to all. :) I started using SPI library of wiringPi recently and it's working wel...
by sparkyPi
Fri Oct 09, 2015 4:06 pm
Forum: C/C++
Topic: wiringPi: Using SPI and I2C in the same program
Replies: 2
Views: 982

Re: wiringPi: Using SPI and I2C in the same program

[email protected] wrote:I can't think of a reason - the SPI and I2C code is fairly separate - no shared global state, etc. ...

I'll see if I can do some tests.

-Gordon
Thank you, Gordon!

If you can't reproduce the issue, or it would help to have a minimum code example from me, I can prepare that.

Best,
sparkyPi
by sparkyPi
Fri Oct 09, 2015 6:31 am
Forum: Other projects
Topic: A Start-Stop button with Shutdown & Powerdown
Replies: 8
Views: 6611

Re: A Start-Stop button with Shutdown & Powerdown

<snip> Maybe sparkyPi can chime in. Thanks, paulv , I'm pretty late to the party, so to speak, but happy to offer my thoughts :) When reading my responses below you might like to refer to this post with schematics of the implementation I use. 1 - Where is the best source to pull-up /INT? I was aimi...
by sparkyPi
Fri Oct 09, 2015 1:24 am
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

Just wanted to post an update of complete schematics showing how I am using the LTC2951-1 on/off controller; using its /INT output (input to Raspberry Pi to initiate the shutdown process) and /KILL input (the "power off" signal from Raspberry Pi implemented by the gpio-poweroff Device Tree overlay)....
by sparkyPi
Fri Oct 09, 2015 12:27 am
Forum: C/C++
Topic: wiringPi: Using SPI and I2C in the same program
Replies: 2
Views: 982

wiringPi: Using SPI and I2C in the same program

Hi everyone, I have been using the wiringPi library (currently on v2.29) (http://www.wiringPi.com) by Gordon Henderson for controlling several I2C devices -- it works great! Thanks Gordon for this fantastic library! :D I recently added an SPI device (NXP MFRC522 RFID reader IC) to my project on SPI ...
by sparkyPi
Mon Aug 24, 2015 2:36 am
Forum: Other projects
Topic: A Start-Stop button with Shutdown & Powerdown
Replies: 8
Views: 6611

Re: A Start-Stop button with Shutdown & Powerdown

Hi sparkiPy, Thank you for taking the time to look at my post. <snip> Going back to the use of the LTC start-stop controller. I have shown that by selecting the right capacitor value for the KILLT pin, there is no need to have the /KILL signal implemented through the kernel at all. The suggestion i...
by sparkyPi
Sun Aug 16, 2015 9:30 pm
Forum: Other projects
Topic: A Start-Stop button with Shutdown & Powerdown
Replies: 8
Views: 6611

Re: A Start-Stop button with Shutdown & Powerdown

This post is a follow-up one from some work done by SparkyPi, to create a button for the Pi with shutdown and power down features. https://www.raspberrypi.org/forums/viewtopic.php?f=107&t=113789 Initially, he wanted to use the Device Tree features to create a needed /KILL signal. I found yet anothe...
by sparkyPi
Sun Aug 16, 2015 8:10 pm
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

The gpio-poweroff feature is very welcome, as long as you know what it really does. If the active-high mode of the gpio-poweroff is used, there should be no problem with the start-up timing issue. However, if you need to drive an active-low device, it is probably more straightforward (avoiding conc...
by sparkyPi
Sun Aug 16, 2015 7:35 pm
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

That's a good question. The answer is that the "Device Tree" processing is in three parts. 1) dt-blob.bin (either the external file or the default one compiled into the start*.elf binaries) is read by the firmware to allow it to set up the initial pin configuration (and perhaps a few clocks as well...
by sparkyPi
Tue Jun 30, 2015 6:59 am
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

@Paul: Sounds good! I will look forward to your update!

Best,
sparkyPi
by sparkyPi
Mon Jun 29, 2015 1:51 am
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

Glad to see you have resolved this together with PhilE. Very interesting collaboration! This is a significant step to add better power control to the Pi. I also use UPS based power controllers to allow the Pi in embedded (server) applications and have documented several on this forum. One How-To is...
by sparkyPi
Fri Jun 26, 2015 8:29 pm
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

@PhilE, thanks so much for your help. I tested your patch in the last update and it works perfectly! Great to see the gpio-poweroff overlay as an official part of the release. This issue is solved :D Cheers!
by sparkyPi
Fri Jun 26, 2015 8:27 pm
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

@paulv, I agree these controllers are very useful in embedded systems - a very elegant way to start and shutdown a system. With on/off controllers like this whenever /KILL is asserted (low in this case) the ENable output (which controls voltage regulators on my custom board which Raspberry Pi plugs ...
by sparkyPi
Thu Jun 25, 2015 7:11 pm
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

@PhilE, thanks for drilling down on the issue and creating a patch with all the necessary Makefile/README and overlay.dts That's really a lot more support than I ever expected. You guys are a great team. :D ...using it in active-low mode requires a custom dt-blob.bin to prevent it from powering off ...
by sparkyPi
Thu Jun 25, 2015 2:57 am
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

Thanks for your input PhilE , and pointing over here from github. I have tried with just the essentials in the overlay: /dts-v1/; /plugin/; / { compatible = "brcm,bcm2709"; [email protected] { target-path = "/"; __overlay__ { power_ctrl: power_ctrl { compatible = "gpio-poweroff"; gpios = <&gpio 26 0>; }; }...
by sparkyPi
Mon Jun 22, 2015 4:48 pm
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Re: Overlay for on/off push-button controller.

Thank you, PhilE, for your prompt reply and giving me some direction on this. I've never submit an Issue on github before; I'll get right on it. I would love to see this feature added :D Edit: And here it is on github . Excellent to see already that it will be included in next update -- can't wait! :D
by sparkyPi
Mon Jun 22, 2015 2:55 am
Forum: Device Tree
Topic: Overlay for on/off push-button controller.
Replies: 40
Views: 18599

Overlay for on/off push-button controller.

Hello everyone, I am trying to write a device tree overlay (using GPIO device tree binding for "power off", see here ) for a push-button on/off controller ( Linear Technology LTC2951-1 ). I attached an image showing the schematic of LTC2951 and Raspberry Pi GPIOs. Unfortunately I've not been able to...

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