Cartft FLEETPC-ARM-300 Series Reference Manual page 15

MCU-controlled power on/off
The MCU-controlled power on/off allows software to turn off system power by issuing a
2
command (via I C channel 1, or GPIO) to the MCU (an 8-bit STM8S MCU).
FLEETPC-ARM-300 provides applications (i2creboot and xsignal) in Linux for MCU's action:
i2creboot –m 0
i2creboot –d xxx –m 1
echo 0 > /sys/class/leds/pwr_gpio/brightness
// this Linux command uses GPIO to inform MCU to turn off system power immediately
The xsignal is a background application persistently monitoring Linux RunLevel.
When Linux executes "reboot" command and RunLevel becomes 6, xsignal will issue
command "i2creboot -d 2 -m 1" to turn off power and turn on power after 2 seconds.
When Linux executes "shutdown –h now" command, RunLevel becomes 0, xsignal will
issue command "echo 0 > /sys/class/leds/pwr_gpio/brightness" to turn off power
immediately.
When the MCU turns off FLEETPC-ARM-300 system power, some components are still
"ON" to monitor power input. These components include MCU, power regulars, power
switches and
over-voltage protection circuit (The grey blocks in below diagram). This means a minimum
power will be dissipated by these components.
All manuals and user guides at all-guides.com
// this command will wait until Linux finishes normal
// system shutdown and then turn off system power.
// this command will immediately turn off system power and
// then turn on system power after xxx seconds, where xxx
// is 1 to 65535. This can be used for system reboot (cold start).
Page 15
FLEETPC-ARM-300 Series