8.
Controlling the E20 from the SM220
The SM220 has two pins dedicated to interfacing with the E20.
•
GPIO_C4 – system reset. Active low. Triggers a hardware reset on the E20.
•
GPIO_F2 – Interrupt / General Use – Tied to GPIO 32 on the E20
GPIO_F2 can be used to signal the E20 that some event of interest has occurred that might want to be
responded to even if a SnapConnect application is not running. Below is a trivial example of how to monitor for
this interrupt being raised:
if [[ ! -d /sys/class/gpio/gpio32/ ]] ; then
echo 32 > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio32/direction
fi
while [[ `cat /sys/class/gpio/gpio32/value` != 0 ]] ; do
sleep 1
done
echo "Got interrupt!"
9.
Factory Restore
Factory restore is accomplished using a USB flash drive.
•
Unzip e20-VERS-installer.zip to the root level of your flash drive
•
Plug into the USB-A port on the E20
•
Power, establish serial connection
•
Interrupt u-boot
•
Execute the following command:
usb start; ext4load usb 0 0x12000000 uImage; ext4load usb 0
0x18000000 imx6s-e20.dtb; setenv bootargs
console=ttymxc0,115200 --no-log root=/dev/sda1 rootwait rw;
bootm 0x12000000 - 0x18000000
•
When the lights turn green, installation is complete and it is safe to remove power to restart the
device.
8
SNAP Connect E20 Users Guide
Preliminary
- Pre-Release
Version
