SBC/Raspberry PI¶
Hardware¶
Power¶
RPI3¶
2.4A Max (typical: 400 - 1300mA)
Function |
Imax (mA) |
|---|---|
Camera |
250 |
Ethernet |
? |
GPIO Pins |
100 |
HDMI |
50 |
Wifi |
? |
I/O Pins¶
GPIO¶
sysfs:
$ echo <pin number> > /sys/class/gpio/export
# For GPIO 4
$ echo 4 > /sys/class/gpio/export
$ ls /sys/class/gpio/gpio4:
* active_low
* direction
* edge
* uevent
* value
$ cat /sys/class/gpio/gpio<pin number>/value
$ echo out > /sys/class/gpio/gpio<pin number>/direction
$ echo 0 > /sys/class/gpio/gpio<pin number>/value
$ echo 1 > /sys/class/gpio/gpio<pin number>/value
I2C¶
Serial¶
Debug Console:
Using Adafruit USB to TTL Serial Cable.
Enable Console:
add enable_uart=1 to bottom of /boot/config.txt
or
use raspi-config
Connect Leads:
Cable Wire Color |
RPI Header Pin |
Pin Function |
|---|---|---|
Black |
6 |
GND |
White |
8 |
TXD |
Green |
10 |
RXD |
SPI¶
Operating Systems¶
Alpine Linux¶
Installation¶
Steps:
Create SD Card
First Boot
Create SD Card:
$ sudo -i
$ dmesg | tail
> sdh: sdh1 sdh2
$ SD_DISK="sdh"
$ VERSION="v3.8"
$ ARCH="aarch64"
$ URL="http://dl-cdn.alpinelinux.org/alpine/$VERSION/releases/$ARCH/alpine-rpi-3.8.0-$ARCH.tar.gz"
$ fdisk /dev/$SD_DISK
> d - delete partitions
> n - create new partition
> t - set partition type (c)
> a - set bootable flag
> p
Device Boot Start End Sectors Size Id Type
/dev/sdh1 * 2048 31116287 31114240 14.9G c W95 FAT32 (LBA)
> w - write and exit
$ mkfs.fat -F 32 /dev/${SD_DISK}1
$ mount /dev/${SD_DISK}1 /mnt/usb
$ cd /mnt/usb
$ curl $URL | tar xvzf - --no-same-owner
$ sed -i -e 's/$/ console=serial0,115200/' cmdline.txt
$ echo enable_uart=1 > usercfg.txt
$ cd ~
$ umount /mnt/usb
$ exit
First Boot:
* Insert SD card
* Connect console cable
* Connect network cable
* apply power
* default loging: root/<blank>
$ setup-alpine
$ VERSION="v3.8"
$ echo "
http://dl-cdn.alpinelinux.org/alpine/$VERSION/main/
http://dl-cdn.alpinelinux.org/alpine/$VERSION/community/
@edge http://nl.alpinelinux.org/alpine/edge/main
@edgecommunity http://nl.alpinelinux.org/alpine/edge/community
@testing http://nl.alpinelinux.org/alpine/edge/testing
" > /etc/apk/repositories
$ apk update
$ apk upgrade
$ apk add nano wget i2c-tools@testing
$ sed -i '/#PermitRootLogin prohibit-password/c\PermitRootLogin yes' \
/etc/ssh/sshd_config
# add private repo key to /etc/apk/keys
# add private repo urls to /etc/apk/repositories
$ lbu commit -d
$ reboot
Raspbian¶
Community¶
TBD