If we have an error in the SPI or I2C transaction we should not change
the state. Otherwise we might read a temperature when the sensor is
reporting pressure and vice-versa.
This commit changes the way libraries headers are included in source files:
- If the header is in the same directory the source belongs to, so the
notation '#include ""' is used with the path relative to the directory
containing the source.
- If the header is outside the directory containing the source, then we use
the notation '#include <>' with the path relative to libraries folder.
Some of the advantages of such approach:
- Only one search path for libraries headers.
- OSs like Windows may have a better lookup time.
- Allows use of hardware floating point on the Cortex-M4.
- Added "f" suffix to floating point literals.
- Call floating point versions of stdlib math functions.
this changes the barometer calculations to floating point. On a MS5611
this is actually about twice as fast as the previous 64 bit
calculations, but gains us more accuracy as we are able to take
advantage of sub-bit precision when we average over 8 samples.
this allows us to use the MS5611 barometer at its full 100Hz sample
rate (80Hz for pressure, 20Hz for temperature). The pressure and
temperature values are averaged between reads without adding any
latency. Previously the driver would throw away values between
readings
This also fixes a race condition in reading from the SPI bus that
could lead to bad values from the barometer
this allows the barometer driver to calibrate and return altitude and
climb rate values. This will be used by the AHRS drift correction code
for vertical velocity
The climb rate uses a 5 point average filter
Believe it or not, changing / 2^31 to >>31 saved 256 bytes in the "d" segment.
The reason is that GCC version prior to 4.3.5 does not have a count_leading_zeros (clz) assembler macro, so it uses a 256 byte lookup table called _clz
The _clz table gets pulled in if you do 64 bit division.
This tiny change is the only place that we do long long division.
Changing to a shift saves 256 bytes of ram.