Flowdeck V2 I2C connection FAIL

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aandrien
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Posts: 4
Joined: Sun Jun 13, 2021 1:58 pm

Flowdeck V2 I2C connection FAIL

Post by aandrien »

Hi all,

I have used the Flowdeck V2 several times without issues, however it doesn't work anymore. There is a problem with the I2C connection, as shown in the output of the console when I start up the CF 2.1:

Code: Select all

SYS: Crazyflie 2.1 is up and running!
SYS: Production release 2021.03
SYS: I am 0x20373357594B5007003C002C and I have 1024KB of flash!
CFGBLK: v1, verification [OK]
DECK_CORE: 1 deck(s) found
DECK_CORE: Calling INIT on driver bcFlow2 for deck 0
ZR2: Z-down sensor [FAIL]
PMW: Motion chip id: 0x:0x
IMU: BMI088: Using I2C interface.
IMU: BMI088 Gyro connection [OK].
IMU: BMI088 Accel connection [OK]
IMU: BMP388 I2C connection [OK]
ESTIMATOR: Using Kalman (2) estimator
CONTROLLER: Using PID (1) controller
MTR-DRV: Using brushed motor driver
EEPROM: I2C connection [FAIL].
STORAGE: Storage check [OK].
IMU: BMI088 gyro self-test [OK]
Error while initializing the PMW3901 sensor
DECK_CORE: Deck 0 test [FAIL].
It must be the Flowdeck itself and not the CF2.1, since with another deck (the LedRing) it shows:

Code: Select all

SYS: ----------------------------
SYS: Crazyflie 2.1 is up and running!
SYS: Production release 2021.03
SYS: I am 0x20373357594B500800460030 and I have 1024KB of flash!
CFGBLK: v1, verification [OK]
DECK_CORE: 1 deck(s) found
DECK_CORE: Calling INIT on driver bcLedRing for deck 0
IMU: BMI088: Using I2C interface.
IMU: BMI088 Gyro connection [OK].
IMU: BMI088 Accel connection [OK]
IMU: BMP388 I2C connection [OK]
ESTIMATOR: Using Complementary (1) estimator
CONTROLLER: Using PID (1) controller
MTR-DRV: Using brushed motor driver
EEPROM: I2C connection [OK].
STORAGE: Storage check [OK].
IMU: BMI088 gyro self-test [OK]
STAB: Wait for sensor calibration...
SYS: Free heap: 20416 bytes
STAB: Ready to fly.
I also tried with other CF2.1s, which have the same problem.

As a possible solution direction I've soldered the pins directly to the Flowdeck (as sugggested here: https://wiki.bitcraze.io/misc:hacks:solderpins), in order to make sure the damaged connector problem (viewtopic.php?p=15667#p15667) wasn't the issue. Also the firmware is the most recent version (2021.03). From visual inspection I can't see any damage the the Flowdeck itself, the connections look fine and the components as well.

Is there something else I can try to fix the Flowdeck V2, or should I just order a new one?

Thanks in advance!
tobias
Bitcraze
Posts: 2339
Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Flowdeck V2 I2C connection FAIL

Post by tobias »

Judging from the error messages I suspect the power to the Flow deck is the problem. Could you check that you have 3v (VCC) to the Flow deck?
aandrien
Beginner
Posts: 4
Joined: Sun Jun 13, 2021 1:58 pm

Re: Flowdeck V2 I2C connection FAIL

Post by aandrien »

Hi Tobias,

Thanks for the fast response!

I measured the voltage at the soldering point on the Flowdeck V2, it is at 2.97-2.98V, so that seems fine.

Then I measured at some more points, using for reference:
https://wiki.bitcraze.io/_media/project ... ematic.pdf
https://wiki.bitcraze.io/projects:crazy ... ds:flow-v2

The voltage at C1 and C2 is at 3V, so the VL53L1X is getting power.

Moving on to the PMW3901MB:
  • C8 and C12 are at 3V, as expected.
  • C7 and R7 are at 1.797V, which seems strange, I would expect them to be at 3V, but perhaps I am mistaken?
  • R8 is at 3V again, other side is around 0.5V.
So it seems that the PMW3901MB is not getting enough power?

After inspection is seems that the Flowdeck is also missing some components, a picture of the deck:
Image
https://imgur.com/a/ybb4B5D

Looks like C4, C10, C11, R1 and R3 are not on the deck. C10 and C11 are not necessary I guess by looking at the schematics. But R1 and R3 look like they're supposed to be there?

That's it for my thoughts, perhaps this helps in figuring out what's wrong. If you need any more info, please let me know!
tobias
Bitcraze
Posts: 2339
Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Flowdeck V2 I2C connection FAIL

Post by tobias »

The voltages looks correct. The PMw3901MB is running on 1.8V but its IO on 3V. What might be a bit strange is 0.5 voltage at R8, would expect it to be at 3V as it is a pull-up to keep it out of reset. I measured on a board here and R8 is 3V on both sides. Can you measure that again?

The missing components are correct as they shouldn't be mounted.
aandrien
Beginner
Posts: 4
Joined: Sun Jun 13, 2021 1:58 pm

Re: Flowdeck V2 I2C connection FAIL

Post by aandrien »

I just checked again, and it's at 0.5V.

I suspected the R8 resistor to be defective, so I soldered a new 47k one between VCC and the side of R8 that was at 0.5V. It's now at 1.13V, but the board still is not working.

Next I soldered a wire directly between the R8 0.5V side and the VCC, forcing it to 3V I hoped. It resulted in VCC to drop to 2.3-2.5V.

So I guess the PMw3901MB is broken? Any things I could try?
tobias
Bitcraze
Posts: 2339
Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Flowdeck V2 I2C connection FAIL

Post by tobias »

Yes it sounds like the PMW3901MB is broken, it does not explain why the VL53L1x isn't working though. Send us an email to support@bitcraze.io and we can work something out.
aandrien
Beginner
Posts: 4
Joined: Sun Jun 13, 2021 1:58 pm

Re: Flowdeck V2 I2C connection FAIL

Post by aandrien »

That's unfortunate, but like all hardware solutions nothing is ever foolproof. Thanks for your help, I will contact support.
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