Home Forums Everything about the Tricopter V4 F3FC reports extreme current draw

This topic contains 60 replies, has 18 voices, and was last updated by  Wiytboi 1 year, 3 months ago.

Viewing 15 posts - 31 through 45 (of 61 total)
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  • #32336

    Mikael
    Participant

    Yepp, it should have arrived by now. I’m sure David will report back as soon as he has had a chance to look into it.

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    #32774

    gizmatron
    Participant

    I’m having same issue.. need to set offset in the 400’s to get displayed current draw anything near zero as it should be.. I’ve ONLY tried it on uart 3 as I have sbus on 1 and the smartport on 2. be interested to see if david can work this out..

    #32816

    sscott
    Participant

    I’d also be interested to hear if anyone has figured out the cause of this issue yet.

    #32866

    gizmatron
    Participant

    my current analyzer just arrived so at least I’ll be able to figure out what it SHOULD be reading. whether that will enable me to get it to ACTUALLY read correct current is another matter

    #32879

    Alright, spent quite a few hours trying to figure this one out.
    Came to the same conclusion as you guys. Current is being reported correctly when OSD is connected on UART1 and UART3.

    Mikaels board that I got seems to be fried. Processor is acting very strange.

    But I hooked up two brand new boards which worked as they should.

    I have never seen this before, but when the OSD is hooked up to UART2 it’s raising the voltage level of the input pins sharing that block of the processor. The UART levels on the OSD is also pretty strange. Seems to be the RX pin that is causing trouble.

    I tied unplugging and plugging in the OSD while the board was powered on and it made the board freeze up and loose connection. Pretty sure that this isn’t supposed to happen. Also pretty sure this could fry the processor, so please don’t try it yourself. Wondering if the impedance on the OSD is too low.

    I’m a bit out of my depth here as I have never encountered anything like this before. It doesn’t make any sense to me why it would influence other pins on the processor. It’s almost like it’s raising the ground.

    I’m going to add a note to the F3FC page reporting this bug so others know of it.

    Anyone with more experience than me that would like to take a look at it?

    #32885

    mcstan
    Participant

    Hi David

    when you say new boards do you mean new OSD broad or F3FC broad ?

    #32902

    sscott
    Participant

    Are both TX and RX wires connected between the F3FC board and the minimOSD? If so, it might be a case that the UART on the OSD board operates at 0-5V, while the UART on the STM32F processor operates at 0-3.3V. In this case, the TX pin on the OSD will pull the RX pin on the STM32F up to 5V at times, which is outside the processor’s spec voltage range.

    Does adding a voltage divider help?

    #32911

    @mcstan new F3FC

    @sscott All the pins we use on the STM32 are 5V tolerant so it shouldn’t be an issue. Voltage divider is not a terrible good idea, better to do a level shifter using a transistor

    #32914

    sscott
    Participant

    @david Ok great, I wasn’t certain if the F3FC board was using the 5V-tolerant I/O pins or not.

    I did however notice a footnote at the bottom of page 59 of the datasheet which says: “To sustain a voltage higher than VDD+0.3 V, the internal pull-up/pull-down resistors must be disabled”.

    This is just wild postulating, as I haven’t looked into the source code much (so ignore me if you wish), but maybe someone more familiar with the firmware will want to look into whether the internal pull-ups (or downs) are accidentally being enabled on UART2.

    #32916

    lauka
    Participant

    It seems that the driver uses internal pull-up when in non-inverted mode and internal pull-down when in inverted mode. When in bidirectional mode (S.PORT) it uses push-pull mode.

    This is same for all UARTs.

    #33391

    gizmatron
    Participant

    I’ll have to look but I’m pretty sure I have sbus on uart2 OSD on uart1 s-port telemetry on uart3 and I’m still showing 12A draw with only USB connected. i’ll verify later

    #33443

    gizmatron
    Participant

    confirmed.. my OSD reads gibberish for current values on UART1 haven’t tried it on UART2.

    #33444

    mcstan
    Participant

    welcome to the club crazy numbers when switching on msp on the F3FC

    I gave up and switch on smartport and now send all the info to my radio and got it to yell at me when i hit 900 mah

    just going to hope David does a power over OSD broad one day, seen they getting more common now.

    #33467

    gizmatron
    Participant

    I use smartport too and it works fine. in actual fact the microminim OSD works fine, timer, battery voltage etc all work, transmit to the FC and are correctly displayed both on screen and on my radio via smartport so voltage alerts are fine, it’s only the current sensor settings that suck. I might just try configuring the cleanflight virtual current sensor instead, see what that does

    #33592

    Sam
    Participant

    Have you guys found a solution to this yet? I didn’t think a simple thing like displaying mah consumed could be so complicated. My sensor readings look within range on Cleanflight with different combinations of boards connected and amounts of throttle, but the displayed number counts up way too fast. I haven’t checked it against a multimeter yet. MinimOSD Micro connected to UART1 UART3.

    Is it even possible for the OSD to read that data through UART? I’d hate to tear it down and add another wire to the board.

    edit: said wrong UART

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