Communication with PCU works

[M-Welsch]

Description

We want a way to communicate with the PCU to control the hardware periphery and the wakeup feature

What happens if we don't do it (aka Why is it important)?

• We cannot dock, power therefore access the hard drive
• We cannot wake the BCU after sleep

Definition of Ready

PCU exposes a virtual serial port

Key Tasks

Write functions that transfer commands over the serial port to the PCU

• [x] dock, undock
• [x] power, unpower
• [x] set current time
• [x] set wakeup time
• [x] power off the bcu

Acceptance Criteria

• [x] when we call these functions, the PCU docks and powers.
• [x] when we set any of these times, it can be read back correctly
• [x] when we set a wakeup time, the supply for the BCU comes back on at the expected time
• [x] when we send the command to power off, we still have enough time to shut down linux before the supply relay opens

[M-Welsch]

cannot tell if the time before power cutoff is long enough because we cannot execute the "shutdown -h now" command yet

[M-Welsch]

Test

• had a stopwatch
• executed sudo shutdown -h now and started the stopwatch
• stopped when power cunsumption decreased significantly (from 300 to around 100mA at 12V) was aronund 5s

Changed default waiting time from 5 to 10s