01-28-2016, 04:13 PM
(01-28-2016, 09:49 AM)patrickhwood Wrote:(01-24-2016, 01:39 PM)JulianM Wrote: Hi Zoidiano0,
there are some apps in Google Play Store to get a "Knock Off" feature, which means you can turn off the screen by double-tap on it.
That's absolutely no problem and don't need any extra processor or battery usage.
This feature has also be implemented into CyanogenMod (since version 11? I don't know exactly).
The main "problem" in your topic is "Knock On".
The device needs an extra processor for this, if the battery should not drain.
But please come back to the main topic.
Feel free to contact me, if you have any questions about Android and Android-running devices
Best regards
Julian
Most capacitive touch panels have an I2C interface and don't require any CPU resources other than an active IRQ to monitor touch events. It's possible to put the CPU to sleep and leave the touch panel active with the touch panel's IRQ set to wake up the CPU on touch activity by calling enable_irq_wake().
The Solomon Systech driver here: https://github.com/patrickhwood/linux/bl.../ssd2543.c sets up the touch panel to wake up the android system on a touch interrupt.
Bingo, the TP (Touch Panel) port is a dedicated I2C with interrupt circuit.
