101 lines
3.6 KiB
Markdown
101 lines
3.6 KiB
Markdown
# Board - CMJCU
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The CMJCU is a tiny (80mm) board running a STM32F103, which contains a 3-Axis Compass (HMC5883L)
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and an Accelerometer/Gyro (MPU6050).
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This board does not have an onboard USB-Serial converter, so an external adapter is needed.
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# Pins
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RX Connections
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| Pin Label | Description |
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| --------- | ----------- |
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| PA0 | Channel 1 |
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| PA1 | Channel 2 |
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| PA2 | Channel 3 |
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| PA3 | Channel 4 |
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| VCC | Power +3.3v |
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| GND | Ground |
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Serial Connections
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| Pin Label | Description |
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| --------- | --------------- |
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| TX1 | Serial Transmit |
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| RX1 | Serial Receive |
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| GND | Ground |
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| 3V3 | Power +3.3v |
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| 5V | Power +5v |
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Power Connections
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| Pin Label | Description |
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| --------- | ----------------------- |
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| Power + | Power - 1 Cell 3.7v Max |
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| Power - | Ground |
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Motor Connections
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In standard QUADX configuration, the motors are mapped:
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| Cleanflight | CMJCU |
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| ----------- | ------ |
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| Motor 1 | Motor3 |
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| Motor 2 | Motor2 |
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| Motor 3 | Motor4 |
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| Motor 4 | Motor1 |
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It is therefore simplest to wire the motors:
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* Motor 1 -> Clockwise
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* Motor 2 -> Anti-Clockwise
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* Motor 3 -> Clockwise
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* Motor 4 -> Anti-Clockwise
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If you are using the Hubsan x4/Ladybird motors, clockwise are Blue(GND)/Red(VCC) wires, anticlockwise
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are Black(GND)/White(VCC)
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If you have wired as above, Motor1/Motor2 on the board will be forward.
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# Connecting a Serial-USB Adapter
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You will need a USB -> Serial UART adapter. Connect:
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| Adapter | CMJCU |
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| ----------------- | -------------------------- |
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| Either 3.3v OR 5v | The correct 3.3v OR 5v pin |
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| RX | TX |
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| TX | RX |
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When first connected this should power up the board, and will be in bootloader mode. If this does not happen, check
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the charge switch is set to POW.
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After the flashing process has been completed, this will allow access via the cleanflight configurator to change
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settings or flash a new firmware.
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WARNING: If the motors are connected and the board boots into the bootloader, they will start
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to spin after around 20 seconds, it is recommended not to connect the motors until the board
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is flashed.
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# Flashing
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To flash the board:
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* Open Cleanflight Configurator
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* Download the CMJCU firmware binary (https://github.com/cleanflight/cleanflight/tree/master/obj/cleanflight_CJMCU.hex)
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* Select "Load Firmware [Local]" and choose the CMJCU binary
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* Tick "No Reboot Sequence" and "Full Chip Erase"
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* Connect the USB->Serial adapter to the board
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* Select the USB-UART adapter from the top left box
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* Click "Flash Firmware"
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* You should see "Programming: SUCCESSFUL" in the log box
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* Click "Connect" -> This should open the "Initial Setup" tab and you should see sensor data from the quad shown
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* Unplug the quad and solder across the 2 "BOOT0" pins - This prevents the board from going into bootloader mode on next
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boot, if anything goes wrong, simply unsolder these pins and the bootloader will start, allowing you to reflash. You cannot
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overwrite the bootloader.
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# Helpful Hints
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* If you are only using a 4 channel RX, in the auxiliary configuration tab, you can add a "Horizon" mode range around 1500
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for one of the the AUX channels which will result in it being always on
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* Enabling the feature MOTOR_STOP helps with crashes so it doesn't try to keep spinning on its back
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* When the power runs low, the quad will start jumping around a bit, if the flight behaviour seems strange, check your batteries charge
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