====== Raspberry Pi Clock on Alpine ======
Rough instructions for now. Will clean up later.


===== Setup Alpine on Pi =====
https://wiki.alpinelinux.org/wiki/Raspberry_Pi

/media/mmcblk0p1/userconfig.txt
<code>
dtparam=audio=off
dtparam=i2c_arm=on
dtparam=i2c1=on
dtoverlay=i2c-rtc,ds3231
dtparam=spi=off
enable_uart=1
dtoverlay=disable-wifi
dtoverlay=disable-bt
dtoverlay=pps-gpio,gpiopin=4
dtparam=act_led_trigger=heartbeat
</code>

Additional Steps:
  * Create a non-root user
  * Install and enable dropbear/openssh
  * Create ext4 partition with the rest of the SD space, mount at /data <code>/dev/mmcblk0p2 /data ext4 rw,relatime 0 0</code>
  * Install dependencies <code>apk add git build-base scons asciidoctor libxslt docbook-xsl python3-dev libcap-dev ncurses-dev</code>

===== Build & Install pps-tools =====
<code>
cd /data
wget https://github.com/redlab-i/pps-tools/archive/refs/tags/v1.0.2.tar.gz
tar zxvf v1.0.2.tar.gz ; cd pps-tools-1.0.2/ ; make
(as root) make install
ppstest /dev/pps0
</code>

===== Build & Install GPSD =====