this is needed to enable probing for a MS5611 on external I2C bus. The
MS5611 looks the same as a MS5525 airspeed sensor, so we can't just
auto-probe. Users will need to enable external barometers
the datasheet says that if you get back zero in an ADC read that the
next value can be corrupt. I have seen this happen on the FMUv1,
leading to bad altitude readings
- reorder and document members.
- remove tentative of vertical alignement
- like was done for accumulated values, move the calibration
values to a struct
This converts MS56XX to use the thread started by SPI/I2C instead of
using the timer thread. This also fixes a possible starvation of the
main thread:
1) INS driver registers itself to be sampled on timer thread
2) MS56XX registers itself to be sampled on timer thread
3) Main thread waits for a sample from INS with
ins.wait_for_sample()
4) timer thread is waiting on update from MS56XX and consequently
the main thread is waiting on an I2C/SPI transfer
Besides this starvation there's another one due to reuse of the timer
lock in order to pump values from the timer thread to the main thread. A
call to the update() method when we have a sample available would need
to wait on any other driver holding the timer lock.
Now there's a lock just to pass the new values from the bus thread to
the main thread with a very tiny critical region, not waiting on any
bus transfers and/or syscalls.
We don't need to expose to other libraries how each backend is
implemented. AP_Baro.h is the main header, included by other libraries.
Instead of including each backend in the main header, move them to where
they are needed. Additionally standardize the order and how we include
the headers.
The advantages are:
- Internals of each backend is not exposed outside of the
library
- Faster incremental builds since we don't need to recompile
whoever includes AP_Baro.h because a backend changed
The configuration of MS5637 is different from MS5611 in 2 ways:
- The PROM is of 112 bytes rather than 128
- The CRC is located in the first MSB of the first word, not the
last one
For CRC calculation we also need to zero out the last (missing) word.
This renames _check_crc() to _read_prom(), which returns false when the
PROM doesn't contain valid data. It also makes it virtual so MS5637 can
override it. This also moves the PROM read to be all in the same place
rather than split between the CRC field and coefficient fields. Finally
calculate_crc() is renamed to crc4() to be shorter and add info on what
it does.
On MS5637 we will need to override the method to read and calculate the
PROM's crc. Thus we need a 2-phase init.
It also makes the constructor of AP_Baro_MS56XX protected since only the
derived classes should instantiate the base one.
This is the same change as done in PX4:
This reduces self-heating of the sensor which reduces the amount
of altitude change when warming up. Apparently some individual
sensors are severely affected by this.
Unfortunately it raises the noise level, but Paul is confident
it won't be a significant issue.
The PSTR is already define as a NOP for all supported platforms. It's
only needed for AVR so here we remove all the uses throughout the
codebase.
This was automated with a simple python script so it also converts
places which spans to multiple lines, removing the matching parentheses.
AVR-specific places were not changed.
As AVR2560 is not supported anymore and do integer operations is
usually faster than float-point the _calculate() implementation was
done using only integer operations and as more close to what
datasheet says.
If there is a read error, reading from the adc will return 0 but moreover,
we need to re-initiate a read or else we are stuck forever.
From MS5611-01BA03 datasheet, p. 10, CONVERSION SEQUENCE:
"After the conversion, using ADC read command the result is clocked out with the MSB first.
If the conversion is not executed before the ADC read command, or the ADC read command is
repeated, it will give 0 as the output result."
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.
Andrew Tridgell
Peter Barker
murata
Jonathan Challinger
night-ghost
Lucas De Marchi
Jacob Walser
Mathieu OTHACEHE
Julien BERAUD
José Roberto de Souza
Caio Marcelo de Oliveira Filho
raspilot
Gustavo Jose de Sousa