I2C3_SCL and I2C3_SDA pins are mixed up

[supersidor]

according to datasheet of STM32F405xx chip PA8 is I2C3_SCL and PC9 is I2C3_SDA
Currently they are mixed up.
I use MATEK F405-OSD with external barometer and this fix solves my issues

[mikeller]

@supersidor: Thanks for this - this target is a legacy target that is not released any more, as it has been superseded by the Unified Target in https://github.com/betaflight/unified-targets/blob/master/configs/default/MTKS-MATEKF405STD.config - interestingly this target does not even specify pins for I2C 3. If they are connected to pads then maybe they should be added?

[supersidor]

PA8 and PC9 have pads on flight controller - they are S4 and S6 pads on PCB. I just checked this for F405-OSD, F405-STD and F405-CTR versions.
I guess it would be nice to have I2C 3 declared but you have more expertise

[mikeller]

@supersidor: See betaflight/unified-targets#259.

[SnowLeopardFPV]

These default I2C 3 resource mapping changes are now preventing motor 4 from spinning if any ESC protocol other than DSHOT is used on the Matek F405-STD boards. The MOTOR 4 resource (pad S4) is already assigned to pin C09 and the MOTOR 6 resource (pad S6) is already assigned to pin A08. So the new I2C 3 resource mapping assignments appear to have caused some kind of resource conflict, but only when using the non-DSHOT ESC protocols.