i.MX Processors中的主题 Reading the User buttons (KEY1, KEY2, etc..)

Reading the User buttons (KEY1, KEY2, etc..)

blsousan — Wed, 20 Jun 2012 21:35:31 GMT

I have my iMX28EVK booting and mounting the rootfs from the host PC. I found that I can control the LED's (LED2 and LED3 on the eval board) by writing the value of 0 - 255 to:

/sys/devices/platform/mxs-leds.0/leds/led-pwm0/brightness

So is there a similar file in the /sys directory where one can read the status of the user buttons? Reading through the docs it looks like the user buttons are routed through LRADC1 (analog to digital converter) and will generate specific digital values that represent each button.

Bills

Re: Reading the User buttons (KEY1, KEY2, etc..)

blsousan — Thu, 28 Jun 2012 22:00:01 GMT

I found out how to read the buttons. Simply read from the /dev/input/event0. It generates a stream of data every time one of the buttons is pressed.

Re: Reading the User buttons (KEY1, KEY2, etc..)

andreass_ — Wed, 24 Oct 2012 11:05:34 GMT

Hi Bill,

one question. How do you find out which button is pressed?
I see no differences between the different buttons.

Could you help me?

Thanks