16 August, 2016 at 22:07 #32336MikaelParticipant
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.
Attachments:28 August, 2016 at 22:26 #32774
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..30 August, 2016 at 01:00 #32816
I’d also be interested to hear if anyone has figured out the cause of this issue yet.31 August, 2016 at 08:52 #32866
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 matter31 August, 2016 at 13:05 #32879RCExplorer – DavidKeymaster
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?31 August, 2016 at 13:25 #32885mcstanParticipant
when you say new boards do you mean new OSD broad or F3FC broad ?31 August, 2016 at 22:11 #32902
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?1 September, 2016 at 09:14 #32911RCExplorer – DavidKeymaster1 September, 2016 at 09:59 #32914
@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 UART2.1 September, 2016 at 10:55 #32916laukaParticipant
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.20 September, 2016 at 10:27 #33391
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 later22 September, 2016 at 17:11 #33443
confirmed.. my OSD reads gibberish for current values on UART1 haven’t tried it on UART2.22 September, 2016 at 18:30 #33444mcstanParticipant
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.24 September, 2016 at 00:55 #33467
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 does27 September, 2016 at 03:08 #33592SamParticipant
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
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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