On Mac OS X, sending the slip packet byte by byte results in an abysmal
performance. The first byte takes up to 160ms to send, and each next
byte approximately 250ms. The packet to request a data block is
typically 7 bytes large, and therefore takes about 1660ms to send.
Because a dive is transmitted as multiple smaller packets (typically
144 bytes without protocol overhead), downloading a single dive can
easily take several seconds.
However, when sending the entire slip packet at once, the time remains
roughly identical to sending just the first byte. The result is that
the time for sending a packet reduces significantly, proportional to
the length of the packet.
Under the hood, the slip packet is now internally buffered, and the
buffer is send only when the entire packet is complete, or whenever the
buffer gets full. But in practice, the buffer is large enough to always
store an entire packet.
In the original bug report, downloading 57 dives took about 40 minutes.
After applying the patch, that time reduced to only 5 minutes!
The new Oceanic OCi appears to be almost identical to the already
supported Oceanic OC1. The most important change is the different
location for the logbook ringbuffer.
The profile ringbuffer appears to be slightly smaller than expected for
some models. For the Mares Matrix (and all compatible devices) it ends
earlier, while for the Icon HD Net Ready it starts later.
This bug resulted in missing dives, because all remaining dives were
getting dropped once a dive that crossed the ringbuffer boundary was
reached.
The logbook ringbuffer appears to start at offset 0x400 instead of
0x240. Since these ringbuffer boundaries have to be taken taken into
account only once the ringbuffer has been filled completely, this bug
affects users with more than 200 dives only. Thus, no surprise it didn't
get noticed earlier.
Several backends require a shutdown command to be send before closing
the connection. If such a command gets cancelled, that might result in
an unclean shutdown. Backends where this is problematic can always
ignore cancellation requests internally, but it's less error-prone (and
much easier) to simply disable the cancellation callback for all
backends, before closing the connection.
This dive computer has the same enclosure as the Mares Puck, but the
wire protocol is that of the Puck Pro. The original software identifies
it as a "Mares Puck 2", and the handshake string also contains the
sequence "PUCK 2", so this string is used to identify the device.
This event is on when accumulating deco time. Once you reach the floor
deco time will start decreasing and the event will stop. Going below the
floor again will re-activate the event.
Signed-off-by: Michael Andreen <harv@ruin.nu>
When using all 16 bits for the temperature, the resulting values are
clearly wrong in some cases. Most likely the upper 4 bits are used to
store something else. Even with only 12 bits, the resulting temperature
range (0-409.5°C) should still be more than sufficient.
In the OSTC3 data format, the 7th bit of the event byte is used to
indicate whether another event byte is present or not. For the OSTC2,
this 7th bit remained unused, and I assumed it would eventually get used
in the same way as the OSTC3 does. But that assumption turns out to be
wrong. Starting with firmware v2.66 the 7th bit is used for a new
bailout event.
This patch leaves the existing logic intact, but except for the OSTC3
format (version 0x23), the maximum number of events bytes is now limited
to just one byte.
The OSTC 3 dataformat does contain the profile length twice: once in the
main 256 byte header, and again in the small profile header. However due
to a firmware bug, both values are not identical. The value in the main
header is wrong and 3 bytes larger than the value in the small profile
header. This bug was fixed in firmware version 0.93.
Unfortunately we rely on the length in the main header to calculate the
number of bytes to read when downloading the dive. The consequence is
that for all dives recorded with firmware 0.93 or later, the length is
calculated incorrectly, and the download fails. Luckily the firmware
version is stored in the main header too, and we can adjust the length
calculation accordingly.
The firmware version and serial number are stored in the final block
of each dive. That makes it very tricky to support the devinfo event
correctly. For an efficient implementation of the fingerprint feature,
the devinfo event should be emitted before downloading the manifests
or the dives. Fortunately it turns out it is actually possible to
retrieve the firmware version and serial number independently, using
the special identifier command.
A shutdown command should be send to the device, before the connection
is actually closed. In the absence of this command, the device will
display an error, even if the data transfer itself was successful!
The only difference with the two other Oceanic OC1 variants is the new
model number. I have absolutely no idea what's the purpose of such a
silly change.
The Mares Matrix, Puck Pro and Nemo Wide 2 have only 256K of memory,
which is 4 times less compared to the Icon HD. However for some unknown
reason, trying to download 1024K succeeds, and these devices just
repeat the same data 4 times. That's why we never noticed the
difference in memory capacity before.
The Suunto DX has support for 8 gas mixes (OC) and 3 diluents (CC).
Because it's still unknown how rebreather dives are stored, we simply
return all 11 gas mixes. For the rest, the DX data format is very
similar to that of the existing Suunto models, with only a few
different offsets here and there.
When the number of parameters is zero, there are no sample values, and
the offset variable is never increased. The result is an infinite loop.
In practice this shouldn't happen because there should always be at
least one sample value (e.g. depth). But if a new data format is
available, which is not yet supported by the parser, we might be trying
to interpret the wrong byte.
A side effect is that the mares_iconhd_extract_dives function now
requires a valid device handle. This shouldn't cause any real problems
because this function will likely become private some day.
The new xml element makes the the gaschange events stand out more
against the other less important events. At the same time it also
demonstrates the decoding of the packed oxygen and helium percentages.
Without the root element the output isn't valid xml. Although the
output is supposed to provide a human readable representation for
internal use only, and thus never really intended for processing by
third-party applications, it doesn't hurt to turn it into valid xml
either.
In the public header files, all symbols are marked extern C. When using
a C compiler, there is usually no problem if the header isn't included
in the C file. But the msvc build system uses the C++ compiler (due to
the use of some C99 features not supported by the msvc C compiler).
Currently all device descriptors are included, regardless of whether
the device is actually supported by the library. If IrDA or USB support
is unavailable, a dummy backend is build which will always fail with
DC_STATUS_UNSUPPORTED. Thus there is no point in listing those devices
as being supported. Doing so will only confuse end-users.
Although the communication protocol of the OSTC3 is nearly identical to
that of the Frog, the different size parameters make it hard to share
the code easily. On top of that, if we ever implement native bluetooth
communication support, we'll need a completely separate backend anyway.
Therefore the Frog backend is simply duplicated, with a few OSTC3
specific changes applied here and there.
The existing ostc parser is upgraded to support the new OSTC3 data
format.
The Frog stores the index of the initial gas mix at the same location
as the OSTC, but the gas mix percentages are at a different offset, and
the number of gas mixes is different too. Parsing all the gas mixes in
advance makes the code easier to read and more future proof.
With the layout descriptors, most hardcoded constants are now in a
central place, which will make it easier to add support for new data
format variants.
If the gas model flag is set to air, the individual gas mix definitions
are ignored, and a single mix with air is returned instead. For non-air
dives, only the gas mixes marked as active are returned.
Sometimes there are garbage bytes present after opening the serial
port, which causes the communication to fail. Flushing the buffers
after a small delay is all it takes to get rid of those bytes.
The React Pro White appears to be a newer variant of the React Pro. For
the communication it uses the newer atom2 protocol, but the data format
remains (almost) the same as the older React Pro.
This model doesn't support a 2 second sample rate. It appears the
possible sample rate values have been shifted by one to map the value
zero to a 15 second sample rate.
To avoid any trouble with possible out of range values, the index is
shifted in a circular way.
