[Bug] CUAV 6X board detection sometimes fails on v1.14.x

[julianoes]

Describe the bug

Sometimes, the board version/revision check for the CUAV 6X fails. I observe this about 1 in 5 reboots, only with v1.14.x.

When it happens, the baros and mag are not getting initialized.

FYI @davids5, @CUAVcaijie

To Reproduce

1. Flash v1.14.x from QGC.
2. Check for baros and mag, or check ver all

You can also add a break point in: https://github.com/PX4/PX4-Autopilot/blob/32aa3263a60d48a960eb8a2ccc50073815250889/platforms/nuttx/src/px4/stm/stm32_common/board_hw_info/board_hw_rev_ver.c#L335

And check dn. It changes slightly on every reboot.

Expected behavior

Correct:

ver all
HW arch: PX4_FMU_V6X
HW type: V6X002001
HW version: 0x002
HW revision: 0x001
PX4 git-hash: b8c541dd7277ed735139d7d1bfb829d61fbe29fb
PX4 version: Release 1.14.0 (17694975)
OS: NuttX
OS version: Release 11.0.0 (184549631)
OS git-hash: de41e7feaeffaec3ce65327e9569e8fdb553ca3d
Build datetime: Oct 19 2023 16:24:32
Build uri: localhost
Build variant: default
Toolchain: GNU GCC, 9.3.1 20200408 (release)
PX4GUID: 000600000000313732373330511200400036
MCU: STM32H7[4|5]xxx, rev. V

Failed:

ver all
HW arch: PX4_FMU_V6X
HW type: V6X002000
HW version: 0x002
HW revision: 0x000
PX4 git-hash: b8c541dd7277ed735139d7d1bfb829d61fbe29fb
PX4 version: Release 1.14.0 (17694975)
OS: NuttX
OS version: Release 11.0.0 (184549631)
OS git-hash: de41e7feaeffaec3ce65327e9569e8fdb553ca3d
Build datetime: Oct 19 2023 16:24:32
Build uri: localhost
Build variant: default
Toolchain: GNU GCC, 9.3.1 20200408 (release)
PX4GUID: 000600000000313732373330511200400036
MCU: STM32H7[4|5]xxx, rev. V

Screenshot / Media

No response

Flight Log

No flying required

Software Version

v1.14.0

Flight controller

CUAV 6X

Vehicle type

None

How are the different components wired up (including port information)

No response

Additional context

No response

[davids5]

@julianoes The dn will fluctuate because of noise. Would you capture the values on your HW when it is good an bad and post them here.

[julianoes]

I remember seeing values between 15 and 21 but I don't have it set up anymore.

[davids5]

I remember seeing values between 15 and 21 but I don't have it set up anymore.

hmm both those values fall in the 1 bucket.

[julianoes]

dn: 15
...
HW arch: PX4_FMU_V6X
HW type: V6X
HW FMUM ID: 0x000
HW BASE ID: 0x002

dn: 19
...
HW arch: PX4_FMU_V6X
HW type: V6X
HW FMUM ID: 0x001
HW BASE ID: 0x002

[davids5]

Can you print it here https://github.com/PX4/PX4-Autopilot/blob/32aa3263a60d48a960eb8a2ccc50073815250889/platforms/nuttx/src/px4/stm/stm32_common/board_hw_info/board_hw_rev_ver.c#L87

[davids5]

Ok I can see that dn scaling is seeing 15 as a 0 @CUAVcaijie What tolerance R's did you use?