In bigpage mode, we always read large pages, regardless of the amount of
bytes requested by the caller. Excess bytes are simply discarded. This
is inefficient because the same large page will be downloaded multiple
times, when requesting more than one 16 byte page from the same large
page. By caching the pages internally, we can greatly reduce the amount
of I/O operations.
In practice, applications and also libdivecomputer's internal algorithm
for downloading the dives will typically request contiguous pages, so we
only need to cache the last page.
This implementation is based on ideas and code contributed by Dirk
Hohndel.
Encoded in every sample. The depth is in multiples of 10 feet which gives
somewhat odd metric stop depth - but rounding to full meters would take
care of that.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
This is ignoring a ton of data that the dive computer provides. But it
gives profile, tank pressure and temperatures - so it's a start.
This patch adds a set_dtr and set_rts call to the serial interface prior
to interacting with the device. This change is required for the A300CS to
talk to the computer.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Some new Oceanic dive computers like the Aeris A300CS support a new read
command that always reads 256 byte pages instead of 16 byte pages, other
versions support reading 128 byte pages.
This patch adds a field to the oceanic_atom2_device_t structure to
indicate which type of device this is. If bigpage mode is enabled, the
algorithm will always request larger, aligned reads and fall back to
standard 16 byte reads otherwise.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
The primary tank, which is the tank connected to the hose and thus the
tank pressure sensor, it not necessary the first tank. The correct tank
index can be found by searching the array for a gas mix with a sensor id
equal to one.
The gasmix value in the sample data is the id of the gasmix. Depending
how the user manipulated the gasmix settings, this id is not necessary
identical to the index into the gasmix array. The array index can be
found by searching the array for a mix with the correct id.
For the Tusa Zen, the header is 16 bytes smaller. With this change, the
gasmixes and the intial temperature are now parsed correctly.
The tank pressure samples have also been disabled manually, because this
is a non-air integrated model that doesn't seem to set the initial tank
pressure to the magic value 10000.
The 6 byte logbook entry gets prepended to the profile data. We need to
take this into account when allocating the memory buffer. Under normal
circumstances this shouldn't be a problem, because a single dive is
usually much smaller than the profile ringbuffer. But it's better to be
on the safe side.
The fingerprint is used unconditionally, regardless of whether it's
explicitly set by the application or not. Therefore it needs to be
initialized properly.
Although the OSTC Sport uses bluetooth communication, the new model
remains fully compatible with the OSTC3, because it provides a virtual
serial port interface. As usual, the new model can be detected based on
the serial number.
For a dive in gauge mode, the gas mixes defined in the header should be
ignored, and no gas change event should be emitted. This is done by
hardcoding the number of gas mixes to zero.
The code to find the offset to the footer and parse the gas mix data is
duplicated in multiple places. Move this code to a single place, and
cache the data in the parser instead.
Gas mixes that have been disabled are stored as a mix with 0% oxygen and
0% helium. This is clearly an invalid gas mix, and it makes no sense to
return it back to the application.
For the Nemo Air, a dive mode with the value 2 indicates gauge mode
instead of freedive mode. With this change, all models from the puck
family now use the same values.
With a time based sample interval, the maximum number of samples for a
single timestamp should be constant. However in practice some devices
occasionally store one or more additional samples with the same
timestamp.
Ignoring those excess samples, allows the parser to proceed, while still
preserving the strict time based interval for the application.
Commit d414da70a42afca0096e0402a426c4ac8d2a2881 added support for a
second Aeris Elite T3 variant. But the parser wasn't updated to take
into account this second model number.
For the Aeris Manta and Sherwood Insight, the header size should be 16
bytes smaller. Due to this mistake not only two samples were missing,
but also the byte offset for the gas mixes were wrong. This resulted in
invalid gas mixes, with oxygen percentages exceeding 100%.
For the older models, gas mixes are disabled by setting their oxygen
percentage byte to 0x00 or 0xFF. Trying to parse such a byte as a valid
percentage results in an invalid gas mix.
Because the device doesn't allow you to enable a gas mix if the previous
gas mix has already been disabled, we can simply stop parsing the gas
mixes once the first disabled gas mix has been found.
The gas mode should not only be taken into account for parsing the gas
mix definitions, but also for the initial gas mix. Because the logic
needs to be kept in sync, it's convenient to have all related code in a
single place, and cache the value.
Because the gas mode takes precedence over the individual gas mix
definitions, we can simplify the code by taking the gas mode into
account immediately when parsing the gas mixes.
In commit 886884ab606def1183d99eca7dec8affefee635e, the custom log
function in the example applications has already been modified to use
high resolution timestamps. But I forgot about the built-in default log
function. So this is basically the same change, but now applied to the
built-in log function.
The extra memcmp check after the tcsetattr call is intended to verify
whether all the changes to the termios structure have been applied
correctly.
But for pty's, some of the termios settings make no sense at all, and
therefore the Linux kernel always does:
tty->termios.c_cflag &= ~(CSIZE | PARENB);
tty->termios.c_cflag |= (CS8 | CREAD);
Thus, instead of ignoring such nonsense termios settings, the kernel
changes the termios structure to reflect what pty's actually do. The
consequence is that these settings will not stick, and cause the memcmp
check to fail.
An example where this affects libdivecomputer, are the two backends that
require odd or even parity (e.g. vyper and iconhd). Here, the kernel
will clear the PARENB flag, and thus cause the memcmp check to fail.
Since this check appears to causes more trouble than it solves, let's
just remove it completely!
The previous commit exposed another issue. The termios structure may
contain padding bytes. Because the content of those padding bytes is
unspecified, they may contain some random data, which causes the memcmp
to fail.
Explicitly initializing the termios structure with memset, will also set
the padding bytes to zero.
Due to a minor mistake, only the first byte was being checked for
equality. Fixed it by changing position of parenthesis.
Signed-off-by: Venkatesh Shukla <venkatesh.shukla.eee11@iitbhu.ac.in>
The Cressi Leonardo does store an indicator for the ascent rate (e.g.
the number of arrows) in the upper two bits. This results in 4 possible
values, ranging from 0 to 3, with the following interpretation:
0.0 - 3.9 m/min No signal
4.0 - 7.9 m/min 1 Arrow
8.0 - 11.9 m/min 2 Arrows
12.0+ m/min 3 Arrows (with STOP icon)
Reported-By: Nick Shore <support@mac-dive.com>
With the exception of the different event mask (single byte 0x80 vs two
byte 0x0100), the OSTC3 bailout event is identical to the OSTC2 variant.
Just as before, the new bailout event is reported to the application as
a normal gas change event.
Currently, the buffer overflow checks take into account the size of the
entire dive. But since the length of the extended sample is stored in
the data, we can actually check for overflows in each sample. The main
benefit is that errors will be caught much earlier now.
An additional advantage is that we can now easily skip any remaining
sample bytes. Normally such bytes are not present, unless a firmware
update introduces a new feature which our parser doesn't support yet.
The Mares Nemo Wide 2 appears to have a slightly larger profile
ringbuffer, which extends to the end of the internal memory. It remains
to be seen whether this is also true for some of the other models. The
Mares Matrix is currently the only model where this is definitely not
the case.
The Hollis TX1 has several new features compared to the other models. It
supports trimix and up to 6 different gas mixes can be configured. It
also has twice the amount of memory, which requires an extra bit for the
ringbuffer pointers.
