I have been working on this project for over 6 months now.Linux Framebuffer drivers for small TFT LCD display modules.
On the web statistics I can see that interest is picking up.
I'm not a user of this project my self, so I need help to find out what features/documentation are missing.
This is my current TODO list
- Power management
Most of the display controllers have deep sleep states. But there is no support for this in fbtft.
This is important when powered by a battery.
- Boot logo/splash screen
Do some research on different solutions and try them out.
- Improved touch calibration
- PWM Backlight
There is only support for on/off control of the backlight through fbtft. PWM support is missing because there is no pwm kernel driver.
With PWM support in fbtft, apps that "know" brightness could control the backlight.
It should be possible to use WiringPi to pwm the backlight outside of fbtft.
- Gamma calibration
All displays has a gamma curve that can be set. This controls the color brightness. Currently there's no way to adjust this, except for using the flexfb driver.
One exception: @rm-hull has made a pull request for the itdb28fb driver. He has provided 6 curves to choose from.
Is there an aplication that does this sort of calibration? Hopefully there is a standard somewhere to hook into.
I have really wantet a tool that can adjust the gamma curcve on all different controllers. But it's difficult. Some has has only one curve, others two, one posisitive one negative.
And the number of registers varies as well. And some registers is for a large adjustments, some for medium, and some for fine.
How can I harmonize this is into an approach that fits all? What's the underlying pattern here?
- Add more drivers. Which one?
The challenge with larger displays (>3") is that they all have a 16-bit databus, which makes it hard to connect to the RPi with it's 17+4 GPIOs.
It is possible, but leaves very few GPIOs for other peripherals. An alternative is to use an interface circuit: https://github.com/notro/fbtft/wiki/SPI ... ce-circuit
- 16-bit databus support
Currently only SPI and 8-bit databus is supported. I only have a rev. 1 board, so someone would have to work with me on this one (or I could buy a rev. 2 board ...).
Is parts of the current documentation weak, or altogether missing in some important areas?
Any spesific improvements that can be done to make it easier for newbies?
- Make it work on BeagleBone
I have one on my shelf (not opened).