Kindle 4 app development using serial port

[tiniik]

Hi guys,

I would like to develop app for Kindle 4, which will show on display something I send there using serial port. Is it even possible? What programming language should I use? And most imortantly, where should I start? I tried some cross compiling c++ Hello world app, but I don't know how to get some output on kindle display.

Thanks for answers in advance.

[knc1]

Originally Posted by tiniik

Hi guys,

I would like to develop app for Kindle 4, which will show on display something I send there using serial port. Is it even possible? What programming language should I use? And most imortantly, where should I start? I tried some cross compiling c++ Hello world app, but I don't know how to get some output on kindle display.

Thanks for answers in advance.

Using the serial port for general purpose I/O is not very practical.

Linux (and *nix in general) is designed to require an "Operator's Console".
On the Kindle, that is the serial port.

So to use the serial port for another purpose, you first need to find something else that the Linux kernel can use as the Operator's Console.
(That is possible - just not easy, even for an expert.)

Better that you use some sort of network connection to the Kindle for your project.

- - - - -

Your other questions are too general to give specific answers to.

[hawhill]

knc1, are you sure about the console? Couldn't the kernel console by redirected to a virtual console (ttyN), just like on a desktop Linux? Well, I'm not sure if the kernel is compiled with support for that, but chances are nobody bothered to disable that.

As for putting graphics onto the screen - there's a myriad of options. It's just a framebuffer device, so anything using that API would work. We implemented our own stuff for koreader (and arguably, one could fork off that for the task at hand). There's Qt , and more exotic things like Nano-X and probably others. The K4 doesn't have an X11 server like the newer models, I think, so that's not an option here. Kindlets are another approach. In general, I'd advise to look at software that is already there and build on top of that.

[knc1]

Originally Posted by hawhill

knc1, are you sure about the console? Couldn't the kernel console by redirected to a virtual console (ttyN), just like on a desktop Linux? Well, I'm not sure if the kernel is compiled with support for that, but chances are nobody bothered to disable that.
- - - - -

Yes, fairly sure.

Ah, no - the console driver is a very "stupid" driver.
(And it isn't re-directed from the first serial port on your desktop either. ).
The virtual consoles are defined by inittab and use a much more sophisticated driver.

It can be re-directed to a "network console" - -
And I think the Amazon kernels have that enabled -
I have seen boot-up dmesg captures that show ip=0 .
(Which turns netconsole off.)

Geekmaster could probably tell us, if he ever got his "Kindle Wall" running.