Manta MP8 v2 shutdown: i2c timeout

General Discussion
81

I hate saying this yet again but right now the goal should be to get the I2C lines coming out of the P10/P19 connectors wiggling. If you don’t see the lines changing, it doesn’t matter whether or not the capacitors are still in place.

In working through this, I am trying to keep the EBB SB2240 as pristine as possible - no soldering until it becomes obvious. Removing parts or soldering/desoldering has the potential of making things a moving target.

Could we please try to figure out why you’re not seeing anything changing on the I2C lines before touching an iron to the board?

@nefelim4ag thank you for joining in here.

From what I’m seeing in your posts, the specified values (sb2240 and i2c1_PB6_PB7) should be correct.

So why isn’t @borysne seeing any changes in the I2C lines - the RC network on the Stop# pins have a tau of 254ms so even with the capacitors in place, we should be seeing something similar to what @borysne saw from the Manta M8P V2.

One thing I just realized I should have asked @borysne - what is the trigger level on your oscilloscope you’re using for probing PB6/PB7? Looking at the latest screen shot:

image

It looks like you’re waiting for a rising edge at 3.6V when you should be looking for a falling edge at something less than 3.3V.

Maybe things are working, but if the trigger isn’t set properly, then we can’t see them.

1 Like
82

Good day to all!)))
I have good news)

  1. I learned to use an oscilloscope)))
  2. I saw a signal on the SCL pin

And this means that from the software side everything works!) it turns out that the capacitor is the problem

There is a voltage drop during the calibration of the eddy chip

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83

to implement your idea! I need to connect pull-up resistors to 3.3v. on Eddy Coil but there is nowhere to get it! you can connect to 5v but on the Manta board it is connected to 3.3v. a voltage conflict is possible and how this will affect is unknown
manta i2c

84

SB2240
SB22401920×1865 444 KB

The capacitor of pin PB7 is most likely on the other side

85

very strange! It looks like there is no capacitor on pin PB7!!! Because after the 1kOhm resistor the track goes directly to the STM microcontroller!!!

SB2240_1
SB2240_11920×1865 448 KB

I looked through everything! PB5, PB6 have a capacitor!!!
PB7 no capacitor!
looks like whoever made the board forgot about it)))
or it didn’t fit on the board)))

86

Okay, time flies
I need to do something! First, I’ll remove the capacitor from the line SCL pin PB6
I won’t touch the 1 kOhm resistor for now! I’ll take measurements and continue!

SB2240_2
SB2240_21726×2469 333 KB

87

And now we were able to measure the frequency
I remind you that these are measurements without a capacitor! But with 1kOhm resistors

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88

Good news.

Now you have to find the other capacitor (which I believe is C37). I’m hoping that you’re pulling the EBB SB2240 out of the printer to do the search.

Other than that, you have a microscope and just get out your DMM and look for it.

89

I looked through everything! PB5, PB6 have a capacitor!!!
PB7 no capacitor!
looks like whoever made the board forgot about it)))
or it didn’t fit on the board)))

SB2240_3
SB2240_31840×2514 563 KB

SB2240_4
SB2240_41823×2320 504 KB

90

what to check with a multimeter?

  1. my multimeter does not measure such capacitors
  2. the capacitor to the GND. must be removed the STM microcontroller can be measured)
91

Okay, let’s move on! I’ll shunt the 1k resistors! and check!

92

What does the I2C waveform look like on the PB6 line compared to the PB7?

93

I didn’t measure it PB7! only PB6 - SCL
what does this give us? the scheme is the same!

94

If you put the two waveforms together on the oscilloscope, like you did above, you’d see if there actually was a capacitor on PB6.

95

I’ll remove the 1k resistors now and then we’ll check

96

and so I removed the 1k resistors and put jumpers!
the problem remains
measurements by lines:

SCL

SCL
SCL800×480 109 KB

SDA

SDA
SDA800×480 109 KB

97

You obviously still have a capacitor on SDA.

I can’t give you any advice other than go through the board with your microscope and your DMM set to check continuity.

When you do your oscilloscope shots in the future, please include both SDA and SCL - it will be important when we’re checking the EDDY Coil communications.

99

I found it but it’s very far away!!! It’s strange, I’ll figure it out now

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100

Do you know why I didn’t find it!!!
its installation doesn’t match the diagram!!!
capacitor C39 is installed between GND and pin PB7
according to the diagram С39 should be between the 1k resistor and GND!!!

101

Review of components that were removed and jumpers installed!
they interfered with the work i2c

SB2240_5
SB2240_51837×2355 393 KB

SB2240_6
SB2240_61820×2420 468 KB