Spectral-Micro-Simple-FOC

SimpleFOC examples for the Spectral Micro BLDC controller. A PlatformIO project that runs the SimpleFOC library on the driver's STM32F103CB in place of the Spectral firmware, with the board's pins, its MT6816 encoder, and two examples: open loop and closed-loop FOC.

Documentation · SimpleFOC docs · Examples · Discord

SimpleFOC is an alternative to the Spectral firmware, the driver's main firmware. The manual's SimpleFOC guide explains the setup.

Install

git clone https://github.com/Source-Robotics/Spectral-Micro-Simple-FOC.git

Open the folder in VS Code with the PlatformIO extension (SimpleFOC's own installation guide has the other ways). PlatformIO fetches SimpleFOC (askuric/Simple FOC@^2.3.2) on the first build; Upload writes src/main.cpp to the driver through ST-LINK.

You need the programming adapter (an ST-LINK with the 1.27 mm pogo-pin adapter for the JTAG pads), or any ST-LINK wired to 3.3 V, GND, SWDIO and SWCLK. The examples print on the driver's UART connector at 115200 baud: read it with the USB-to-serial adapter as in The serial terminal (3.3 V only).

Warning

This replaces the bootloader. This project has no upload offset, so an upload with the programming adapter writes SimpleFOC at 0x08000000, over the bootloader. Firmware updates over UART or CAN stop working. To go back to the Spectral firmware, install the bootloader again as in Installing the bootloader on an older board, then flash a release.

Quick start

The heart of examples/open_loop_example.cpp, which spins the motor in open loop (// ... marks the lines left out here):

#include "Arduino.h"
#include "SimpleFOC.h"

// Driver PWM pins
#define PWM_CH1 PA_2
#define PWM_CH2 PA_1 
#define PWM_CH3 PA_0 

// ...

// BLDC motor & driver instance
// BLDCMotor motor = BLDCMotor(pole pair number, phase resistance (optional) );
BLDCMotor motor = BLDCMotor(11);
//  BLDCDriver3PWM( pin_pwmA, pin_pwmB, pin_pwmC )
BLDCDriver3PWM driver = BLDCDriver3PWM(PWM_CH1, PWM_CH2, PWM_CH3);

//target variable
float target_velocity = 0.1;

void Init_pins();

void setup() {  

  // Init driver enable pins and LED
  Init_pins();

  // pwm frequency to be used [Hz]
  driver.pwm_frequency = 20000;
  // power supply voltage [V]
  driver.voltage_power_supply = 24;
  // Max DC voltage allowed - default voltage_power_supply
  driver.voltage_limit = 5;
  // driver init
  driver.init();
    // link the motor and the driver
  motor.linkDriver(&driver);
  motor.controller = MotionControlType::velocity_openloop;

  // init motor hardware
  motor.init();
  // ...
}

void loop() {
  // open loop velocity movement
  // using motor.voltage_limit and motor.velocity_limit
  motor.move(target_velocity);
  // monitoring function outputting motor variables to the serial terminal 
  motor.monitor();

}

// ...

The pole pairs (BLDCMotor(11)) and the supply voltage (driver.voltage_power_supply = 24) are set in each example: change them for your motor and supply.

The board in SimpleFOC

How the examples set up the Spectral Micro:

Signal	Pins	In the examples
PWM, phases A, B, C	PA2, PA1, PA0	BLDCDriver3PWM, 20 kHz
Encoder, MT6816 on SPI	MOSI PB5, MISO PB4, CLK PB3, CS PA15	MagneticSensorMT6816 on SPIClass SPI_2(MOSI, MISO, CLK)
Inline current sense, two phases	PA4, PA3; 0.025 Ω shunts, amplifier gain 20	defined, not used yet
Serial, the UART connector	TX PB6, RX PB7	HardwareSerial Serialx(RX_COM, TX_COM), used as Serial, 115200 baud
Driver enable pins and LED	PA9, PA8, PA10, PB15, PB14, PB13	outputs, set HIGH by Init_pins()

Works with

	Version
Spectral Micro BLDC controller	PCB v2.0 (Hardware revisions)
SimpleFOC	2.3.2 (askuric/Simple FOC@^2.3.2), the release the manual's guide was tested with
SimpleFOC drivers library	1.0.8, in lib/Arduino-FOC-drivers-master (for the MT6816 encoder)
PlatformIO	platform ststm32, board genericSTM32F103CB, framework arduino, upload with stlink

Back to the Spectral firmware and its releases: Firmware in the manual.

Examples

In examples. PlatformIO builds and uploads src/main.cpp: to run an example, copy it over that file.

Example	What it does
open_loop_example.cpp	spins the motor in open-loop velocity mode, without the encoder, at 0.1 rad/s with the driver's voltage limit at 5 V, and prints SimpleFOC's monitor output on the serial port
voltage_torque_example.cpp	closed-loop FOC with the MT6816 encoder: aligns the sensor at 3 V, then runs velocity control on voltage torque control (space-vector PWM, voltage limit 8 V) toward 60 rad/s and prints the target, velocity, angle, Uq and Iq; the lines for torque and angle control are there, commented out
src/main.cpp	the voltage-torque example with a target of 6 rad/s

Learn SimpleFOC

The SimpleFOC forum and Discord are the best place to look for help when you develop with the SimpleFOC library. To go further: Getting started, Writing the code and the SimpleFOC Driver and Support Library.

Community

Ask in Discussions, chat on Discord, report a bug in Issues. Follow Source Robotics:

Licensing

The examples are under the MIT License; the SimpleFOC drivers library in lib/ keeps its own MIT License.