Debugging

You can easily debug your Nucleo code by communicating with it via serial. To do this, install PuTTY and connect the Nucleo board directly to your PC.

First, check the COM port of the device (in Device Manager) and then configure PuTTY as follows:

• Connection type - Serial

• Speed - 115200

• Serial line - COMxx

• Terminal → Local echo - Force on

• Terminal → Local line editing - Force on

Go to Session and press Open.

Once PuTTY is running, a successful connection is indicated by the message:

I'm alive

After this message appears, you can send commands to the Nucleo. After each message, press Ctrl+M, Ctrl+J and then Enter.

Power States

The Nucleo has 3 power states: KL0, KL15 and KL30. All designed as a safety feature:

• KL0 Nothing is working. whatever command you send or ask from the Nucleo, will be discarted.

• KL15 Only the interaction with the sensors work, actions like: reading data from IMU, reading data regarding instant consumption, total voltage, autonomy…

• KL30 Enables also the control of the vehicle. Now, messages like: set speed, set seering angle, set movement duration will work.

The Nucleo has a PowerManager, used to protect your work and to increase your safety. Mainly, it does the following:

• If the battery drops below 7.2 Volts → a warning is sent periodically via serial.

• If the battery drops below 7.0 Volts → an error is sent and the Nucleo enters sleep mode.

• After battery replacement, the Nucleo can receive the new capacity via serial (no rebuild required)

Message Structure

Nucleo expects messages with the following format:

#command:val1;val2;valx;;\r\n

And, for each command that it receives, it sends back the following structure:

@command:response1;response2;responsex;;\r\n

Where, command identifies the message, values are ended by a ;, while ;\r\n signals the end of the message.

The commands sent are

command	Description	value	Example request	Example response
speeding	Sets the target speed of the vehicle	signed int Speed [mm/s] (-500,+500)	#speed:60;;\r\n	@speed:60;;\r\n
steering	Sets the target steering of the vehicle	signed int steer [deg*10] (-230,+230)	#steer:180;;\r\n	@steer:180;;\r\n
braking	Sets the vehicle in brake state but allows to set the steering	signed int steer [deg] (-23,+23)	#brake:180;;\r\n	@brake:180;;\r\n
battery enable	Enables/Disables publishing total battery value	bool	#battery:1;;\r\n	@battery:1;;\r\n
instant enable	Enables/Disables instant consumption value	bool	#instant:1;;\r\n	@instant:1;;\r\n
imu enable	Enables/Disables imu publishing values	bool	#imu:1;;\r\n	@imu:1;;\r\n
Controlled move	Sets the velocity control duration i.e. a specific movement for a period of time	signed int Speed signed int Steer signed int time [deciseconds] (0,n)	#vcd:80;-130;121;\r\n	@vcd:80;-130;121;;\r\n
kl	Sets the power state of the nucleo	unsigned int state [0,15,30]	#kl:15;;\r\n	@kl:15;\r\n
batteryCapacity	Sets the capacity of the battery/s	unsigned int mAh (0,n)	#batteryCapacity:12000;;\r\n	@batteryCapacity:12000;;\r\n
resource enable	Enables/Disables resource monitor publishing	bool	#resourceMonitor:1;;\r\n	@resourceMonitor:1;;\r\n

Information received

type	Example response	Description
Battery level	@battery:7800;;\r\n	Signals the battery level is 7.8V.
Instant consumption	@instant:1;;\r\n	1 mA consumed in the last second(frequency can be modified).
Warning battery level	@warning:0;1;13;;\r\n	possibly 0 hours, 1 minute and 13 seconds until sleep.
Error battery level	@shutdown:ack;;\r\n	Nucleo going into shut down mode.
imu data	@imu:1,2,3,4,5,6\r\n	roll,pitch,yaw (deg) and accelx,accely,accelz (m/s).
Velocity-control-dur	@vcd:0;0;0;;\r\n	The movement has finished.

Limits

The Nucleo has a few limits, as follows:

• The maximum speed is 500 mm/s.

• The maximum steering angle is 25°.

• The maximum time for a controlled movement is 255 deciseconds (25.5 seconds).

• The maximum frequency for the imu is 6.67 Hz (150 ms).

Tip

If you experience inconsistent behavior during debugging, double-check the power state and message formatting.