The maximum depth value is stored in the dive header. There is no need
to parse the profile data to obtain it. This also avoids returning a
zero depth when the profile data is no longer available.
A few other fields (e.g. average depth, atmospheric pressure and
temperature) are also present in the dive header.
For dive computers where the reference time (epoch) of the device is
unknown, libdivecomputer uses the current time of the device (devtime)
and the host system (systime) to synchronize both clocks.
Currently, both timestamps are passed directly to the constructor of the
parser. With the new public function, the application can adjust the
timestamps afterwards.
Some dive computers store the depth as an absolute pressure value (in
bar). To convert to a depth value (in meters), the atmospheric pressure
and water density are required. For dive computers that do not have
those values available, libdivecomputer uses a default value. With the
new public api functions, applications can adjust those default values.
Some dive computers already provided a backend specific calibration
function. Those functions are now deprecated. They are kept around to
maintain backwards compatibility for now, but they will be removed in
the next version.
Report the decompression algorithm (Buhlmann, VPM, RGBM or DCIEM), and
if available also the parameters. For now only the conservatism setting
is supported, and for the Buhlmann algorithm also the Gradient Factors
(GF).
For dives with a timestamp that is larger than the current device time
(e.g. in the future), the clock synchronization produces incorrect
values. In that case, the time difference suddenly becomes negative,
which corresponds to a large positive value as an unsigned integer.
Under normal circumstances, this scenario can't happen. But sometimes
actions such as battery replacements or firmware upgrades can cause the
internal clock to reset.
The Reefnet devices shouldn't need this fix, because their internal
clock can't be changed, but it doesn't hurt either.
Since the clock synchronization has been removed (see commit
a1962558412b8c89a79656992c8e7f4d001065c2 for the details), those
parameters serve no purpose anymore.
The command to change the OSTC settings has a variable length payload (1
to 4 bytes). Therefore, the expected number of bytes is only know after
evaluating the first option index byte. Due to the limited UART buffer
in the OSTC, sending the remainder of the packet immediately after the
first byte, can cause the OSTC to get out of sync.
Introduce a small delay between sending the option index and the
remaining parameters to avoid this problem.
The latest firmware does store some additional information for each
tank. Right now it's not really used for anything yet, but it's
available for future use.
In the older Predator-like data format, the 4th opening/closing record
is the last one. To avoid accidental use of the higher ones, leave them
undefined.
During the download, the model number is obtained from the hardware type
because the model number isn't available before downloading the first
dive. Since the list with available hardware types is incomplete, the
correct model number is not always available. However, during parsing
the correct model number is available in the final block.
Starting with log version 8, the dive mode is stored in one of the
opening records. For backwards compatibility with older firmware
versions, the autodetection based on the status field in the sample data
is kept as a fallback mechanism.
In the latest OSTC hardware, the Telit/Stollman bluetooth module has
been replaced with a u-Blox Nina B2 bluetooth module. This new module
supports BLE data packets of up to 244 bytes (corresponding to an ATT
MTU of 247 bytes and a LL PDU payload size of 251 bytes).
For some BLE enabled models, like the Oceanic Pro Plus X, Aqualung
i750TC, Sherwood Sage and Sherwood Beacon, the BLE handshake command
is not supported and therefore disabled.
However, based on a bug report by a user with two Aqualung i770R dive
computers, this detection mechanism based on the dive computer model
number isn't sufficient. Allthough the two devices have the exact same
firmware version (2A), the handshake command only works on the newest
unit, and fails with a NAK response on the oldest unit.
Remove the model based detection and always try to send the handshake
command and rely on the NAK response to ignore the failure instead. An
additional advantage is that we no longer have to (manually) maintain a
list with the model numbers where the handshaking is known to fail.
When the dive computer receives a command it doesn't support, it sends
back a single byte NAK (0xA5) packet instead of the expected ACK byte
(0x5A) at the start of the packet. Retrying is pointless in this case,
because the next attempt will also fail. Instead, return immediately
with an appropriate error code, and let the upper layers handle the
unsupported command.
Note that the detection is currently only enabled for BLE communication.
The Uwatec/Scubapro dive computers are confirmed to internally use the
approximated standard gravity (10.0 m/s²) for the depth conversion.
Allthough this is technically wrong, users expect to get the same depth
values as their dive computer shows.
This partially reverts commit cfc9ddc380bdc5616893fc2af4e05204b5500ea2.
