Sensors - Add clean mbed + LSM6DSOX example

[ladislas]

now that we know that the nucleo and the LSM6DSOX are working fine, let's build a clean example with mbed and the only the sensor drivers.

It would be nice to compare different drivers and see what works best for us.

[YannLocatelli]

Première comparaison effectuée, je remets ici le contenu de l'analyse et résultat:

Introduction

In order to pick the right driver among proposed list (see README.md in above directory).

Different criteria could be :

• Driver update
• Differences in files
• Modifications to do (mbed compatiblity)

Presentation of drivers

• mbed-ST_LSM6DSOX refer to LSM6DSOX driver on mbed, it is published by ST (manufacturer) [Link].
• github-STMicroelectronics_STMems_Standard_C_drivers refer to LSM6DSOX driver on github, it is published by STMicroelectronics (manufacturer) [Link].
• github-stm32duino_LSM6DSOX refer to LSM6DSOX driver on github, it is published by stm32duino for Arduino application [Link].

[YannLocatelli]

[Criteria] Driver update

Date of writing: 13 May 2020

• mbed-ST_LSM6DSOX has 1 commit, the last was 10 July 2019.
• github-STMicroelectronics_STMems_Standard_C_drivers has 515 commits, the last was 8 May 2020.
• github-stm32duino_LSM6DSOX has 7 commits, the last was 10 March 2020.

[YannLocatelli]

[Criteria] Differences in files

Several files were generated in compare folder, they represent differences in code among different drivers files.

Drivers’ names were replaced by numbers in order to simplify:

1 : mbed-ST_LSM6DSOX
3 : github-stm32duino_LSM6DSOX
3_old : github-stm32duino_LSM6DSOX (25 July 2019)

_old refer to a previous version, contemporary of last version of driver on mbed.
(later) refer to current version of the driver.

(Diff in color available with Sublime Text software.)

mbed-ST_LSM6DSOX and github-STMicroelectronics_STMems_Standard_C_drivers

Ressources

mbed-ST_LSM6DSOX commit is similar to commit 88cfaac89e885c2ccbbbf924912230b13be77e4f of github-STMicroelectronics_STMems_Standard_C_drivers , the only difference between both is different I3C value in register but don’t have impact on normal running.

Other differences between last version of both drivers can be seen in history (11 commits ago at this time).

Major differences

• LSM6DSOXSensor.* files missing in github-STMicroelectronics_STMems_Standard_C_drivers.
• (later) add group Basic configuration [Link] with a lot of new functions and associated struct.
• (later) rework lsm6dsox_all_sources_get() and all lsm6dsox_pin_int[1/2]_route_[set/get]() with all associated struct.
• (later) add struct ucf_line_t for .ucf files (Machine Learning model).
• (later) add lsm6dsox_timestamp_rst().

Minor differences

• (later) fix in lsm6dsox_pin_int2_route_set().
• (later) add in lsm6dsox_xl_data_rate_set() and lsm6dsox_gy_data_rate_set() checking data rate constraints of Finite State Machine (FSM) and Machine Learning Core (MLC).
• (later) remove LSM6DSOX_PEDO_ADV_MODE.
• (later) replace lsm6dsox_ctx_t by stmdev_ctx_t.
• (later) replace LSM6DSOX_XL_ODR_6Hz5 by LSM6DSOX_XL_ODR_1Hz6.
• (later) add bytecopy()

[YannLocatelli]

[Criteria] Differences in files

Several files were generated in compare folder, they represent differences in code among different drivers files.

Drivers’ names were replaced by numbers in order to simplify:

1 : mbed-ST_LSM6DSOX
3 : github-stm32duino_LSM6DSOX
3_old : github-stm32duino_LSM6DSOX (25 July 2019)

_old refer to a previous version, contemporary of last version of driver on mbed.
(later) refer to current version of the driver.

(Diff in color available with Sublime Text software.)

mbed-ST_LSM6DSOX and github-stm32duino_LSM6DSOX

Ressources

• 1-3_old (lsm6dsox_reg_c).diff
• 1-3_old (lsm6dsox_reg_h).diff
• 1-3_old (LSM6DSOXSensor_cpp).diff
• 1-3_old (LSM6DSOXSensor_h).diff
• 3_old-3 (lsm6dsox_reg_c).diff
• 3_old-3 (lsm6dsox_reg_h).diff
• 3_old-3 (LSM6DSOXSensor_cpp).diff
• 3_old-3 (LSM6DSOXSensor_h).diff

Major differences

• MotionSensor and GyroSensor in LSM6DSOXSensor.* are mandatory in mbed-ST_LSM6DSOX.
• Wire and TwoWire used in github-stm32duino_LSM6DSOX instead of DevI2C in mbed-ST_LSM6DSOX.
• Attach(), Enable() and Disable() functions are missing for both interrupts (INT1, INT2) in github-stm32duino_LSM6DSOX.
• In github-stm32duino_LSM6DSOX, I3C is disabled in class LSM6DSOXSensor constructor.
• SPI in LSM6DSOXSensor.* is mandatory in github-stm32duino_LSM6DSOX.
• io_read() and io_write() are slightly different but do same task in both drivers.

Minor differences

• Constructor of class LSM6DSOXSensor in github-stm32duino_LSM6DSOX is equivalent as Constructor + init() of class LSM6DSOXSensor in mbed-ST_LSM6DSOX.
• (later) In github-stm32duino_LSM6DSOX, 2 new functions in LSM6DSOXSensor.* act as bridge to existing functions in lsm6dsox_reg.* (Get_MLC_Status() and Get_MLC_Output())
• enum LSM6DSOXStatusTypeDef in github-stm32duino_LSM6DSOX.
• float_t in mbed-ST_LSM6DSOX replaced by float in github-stm32duino_LSM6DSOX
• Lot of virtual functions in mbed-ST_LSM6DSOX.
• Except functions mention above, all functions are identical but with different names.

[YannLocatelli]

[Criteria] Modifications to do (mbed compatiblity)

• mbed-ST_LSM6DSOX: fully integrated (driver and above layer) in mbed.
• github-STMicroelectronics_STMems_Standard_C_drivers: driver is compatible with mbed, not examples that need a BSP. No above layer is provided.
• github-stm32duino_LSM6DSOX: driver (lsm6dsox_reg.*) is compatible but above layer (LSM6DSOXSensor.*) is made for arduino and have to be adapted to mbed.

[YannLocatelli]

Conclusion

Pros & Cons

• mbed-ST_LSM6DSOX
  • pros
    • ✅ Fully integrated to mbed
  • cons
    • ❌ No update
    • ❌ Dependencies to third libraries (Motion, Gyrosensor, DevI2C, Component)
• github-STMicroelectronics_STMems_Standard_C_drivers
  • pros
    • ✅ Still update with new functions and fixes
    • ✅ Driver compatible with mbed
  • cons
    • ❌ Missing abstraction layer LSM6DSOXSensor.*
    • ❌ Examples need ressources and modifications to be functionnal
• github-stm32duino_LSM6DSOX
  • pros
    • ✅ I3C disabled at beginning
    • ✅ Additionnal functions for MLC status
  • cons
    • ❌ Modifications of I2C and SPI for mbed compatiblity
    • ❌ Poor update
    • ❌ No interrupt handler

Suggestion

It is a necessity to stay up to date, so driver lsm6dsox_reg.* should be the one provided by manufacturer on github.

A new abstraction layer LSM6DSOXSensor.* can be done based on drivers of mbed and stm32duino versions but also recent add group Basic configuration on ST version on github.
However only relevant functions should be kept and dependencies should be removed.

[ladislas]

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