Inav: Support magnetometer connected to SDA1 / SDC1 on HAKRC-MiniF4

[alexbirkett]

Current Behavior

The HAKRC-MiniF4 is one of only a few 20x20mm flight controllers with built in barometer. INAV is currently supported using the OMNIBUSF4V3 target.

The HAKRC-MiniF4 has a JST connector that has a UART and a i2c pins (SCL1 and SDA1) broken out on it that could possibly be used to connect a GPS / magnetometer module e.g Beitan BN-880 .The instructions suggest the magnetometer is connected to SCL2 and SDA2 which means some messy soldering and using up pads that could be used for something else:

Desired Behavior

Make it possible to connect a magnetometer to SC1 / SDA1 on the HAKRC-MiniF4.

Suggested Solution

Create a new target specifically for the HAKRC-MiniF4 that uses USE_I2C_DEVICE_1.

Who does this impact? Who is this for?

People using HAKRC-MiniF4 with external GPS / magnetometer module.

[wx4cb]

that looks like a cool little board combo. got links to the parts you're using ? I might use it in a new nano goblin i'm doing

[alexbirkett]

that looks like a cool little board combo. got links to the parts you're using ? I might use it in a new nano goblin i'm doing

https://docs.google.com/spreadsheets/d/1YthgX-AxWWoiD1XvqMCrX5uiW7JgQVIPsdHQczLHrJQ/edit?usp=sharing

[alexbirkett]

I've tried various permutations and combinations of the following to attempt to make it possible to connect the magnetometer to SCL1 and SDA1:

• Remove #define USE_I2C_DEVICE_2 and add #define USE_I2C_DEVICE_1
• Disable features that use PB6 and PB7
• Remove #define MAG_I2C_BUS BUS_I2C2 and add #define MAG_I2C_BUS BUS_I2C1

None of this worked. Could there be some extra circuitry connected to SCL2 and SDA2 that is not connected to SDA1 / SCL1? There appears to be an open circuit from the pads to the pins on the IC. How can I debug this?

Changes here:
https://github.com/alexbirkett/inav/commit/a7c63d5a4bc39b57ae5c5597fb3c45735fa7b485

This is the second time that I've tried and failed to remap resources. I'd really like to figure out what I'm doing wrong.

[alexbirkett]

@atobiese
`#define I2C1_SCL PB6

define I2C1_SDA PB7` fixes it! Thanks.

[alexbirkett]

This issue is not fixed @shellixyz. I hope I can submit a PR that fixes it.

[stale[bot]]

This issue / pull request has been automatically marked as stale because it has not had any activity in 60 days. The resources of the INAV team are limited, and so we are asking for your help.
This issue / pull request will be closed if no further activity occurs within two weeks.

[msfujino]

I modified and remapped HAKRC MiniF4.
I think this information will be helpful for you.

[chobitsfan]

hi @msfujino
May I ask a question? Do I need to physically rewire PA1 to LED? Or you mean it has PA1 has been rewired to LED when board come out? Thank you very much

[msfujino]

Hi chobitsfan

Because I wanted to connect WS2811_LEDStrip to this LED terminal, I cut the pattern, jumpered the PA1 and LED terminal, and assigned PA1 to WS2811 drive signal.
If you do not use this LED terminal, you do not need pattern cutting and jumper wiring.

msfujino

[chobitsfan]

hi @msfujino thank you
You do rewiring because originally the LED connector in hakrc mini f4 is connected with SCL. Is it correct? thank you

[msfujino]

Hi chobitsfan
The resistance between PB6-LED-SCL is almost zero. The same waveform as PB6 is observed with LED and SCL. Although I did not see the pattern directly, I think that PB6-LED-SCL is connected.
msfujino

[chobitsfan]

hi @msfujino thank you very much. I got it
It is strange that hakrc connected LED and SCL together. It do not seems make sense?

[Ex4nder]

Thank you very much @msfujino, your post solved my problems both in Betaflight and Inav

[msfujino]

Hi Ex4nder, I am glad to help you.
It is difficult to solder the jumper directly to PA1(pin 15), so I use PA0(pin 14) for LEDstrip by soldering the jumper to RSSI pad that I do not use.

[Ex4nder]

I didn't configure LED pin yet, and right now I've an error I can't arm because of invalid LED setting, but I will like more to enable hardware serial port 4 on PA0/PA1 for lidar and optical flow, and use maybe beeper pin for the led, beeping with ESCs. I still have to read well the datasheet to see if it can be done. About RSSI I also think I don't need it, because I've telemetry on fport (serial 1 TX in half duplex)
PS. There's also a unsoldered connector, with some pins available, I think it was planned to be for tower setup of esc, did you already map it?

[msfujino]

The ESC tower connector has 12 pins, but 2 pins each are connected together (6 pairs).
Since it is used for VBAT, GND, S1, S2, S3, and S4, I don't think it is possible to remap other functions.

[Ex4nder]

UPDATED!

No, it's not, I also checked yesterday night.
In the end I have working for now:

Serial TX1/RX1(PA9) as f.port [half duplex]
Serial TX3 (PB10), RX3 (PB11), Benewake lidar rangefinder
Serial TX4/RX4 (PA0) (rssi pin) Smart audio VTX control [half duplex]
Serial TX6(PC6) ,TX6(PC7) BN880 GPS
I2C_1 (PB7,PB6) BN880 Magnetometer
PA10 WS2812 LEDStrip Timer 1 channel 3

In target.c
DEF_TIM(TIM1, CH3, PA10, TIM_USE_LED,0, 0)

Only Buzzer is missing now to be installed, I don't plan using a blackbox.

[msfujino]

It took time to set up the compilation environment, but I remap and use FCs which are not supported by iNav. The betaflight target files are very helpful.