DART-6UL WakeableGPIO: Difference between revisions
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MX6UL_PAD_SNVS_TAMPER1__GPIO5_IO01 0x1b0b0 /* WAKE gpio */ | MX6UL_PAD_SNVS_TAMPER1__GPIO5_IO01 0x1b0b0 /* WAKE gpio */ | ||
</pre> | </pre> | ||
= Enter memory retension = | = Enter memory retension = |
Revision as of 13:56, 25 April 2016
\The power domains of all pins of the SOM are switched off in memory retention mode.\ => All GPIOs lose their state.
The only domain that remains alive is RTC domain (SNVS) and the only pins that still accessible are bank 5 of the GPIO.
The DART-6UL provides 4 external GPIO pins that are a part of bank 5, and can be used for waking the system up and for controlling external peripherals in sleep mode.
In teh below example we will use GPIO5_1 to wake up the system. This pin is exposed on J2.64 of the SOM and on pin J6.6 of the EVK.
Define GPIO as a key pad
Add the following section to the imx6ul-var-dart.dtsi file, right after leds section:
gpio_keys { compatible = "gpio-keys"; #address-cells = <1>; #size-cells = <0>; autorepeat; button@21 { label = "GPIO Key UP"; linux,code = <103>; gpios = <&gpio5 1 1>; gpio-key,wakeup; }; };
Add GPIO pad configuration
Add the following section to the imx6ul-var-dart.dtsi file, into pinctrl_hog_1 group:
MX6UL_PAD_SNVS_TAMPER1__GPIO5_IO01 0x1b0b0 /* WAKE gpio */
Enter memory retension
After this command the system will enter memory retension mode.
The serial console will stop responding, all not needed power supplies will be shut down.
You can see that LEDs D30, D27 will turn off on the EVK.
$ echo mem > /sys/power/state
Wake up the system
Connect pins J6.6 and J6,8 with a jumper. It will wake the system up.
You can also press PWR button to wake up the system.