With just 12 bits, the depth values are limited to at most 40.95m.
However for some deeper dives, this appears to be wrong. The next two
higher bits, which were previously unknown, are also part of the depth.
This increases the maximum depth to 163.83m.
The Sporasub SP2 uses a very simple communication protocol and memory
layout, but with some unusual aspects:
Dives are artifically limited to a maximum of 6000 samples.
Unlike all other dive computers, the dives are not stored in some kind
of ringbuffer structure. Once the memory is full, no new dives can be
recorded. The existing dives need to be erased first, and the dive
computer will start recording again at te start of the memory area. The
Sporasub application has an "Auto-clear watch memory after data
transfer" feature for this purpose.
I didn't implement a more efficient download algorithm because
downloading a full memory dumps takes less than 10 seconds.
