AVR172 : Atmel BLDC control on ATAVRMC310 with ATmega32M1 Documentation

License

Use of this program is subject to Atmel's End User License Agreement.

Please read file LICENSE.TXT for copyright notice.

Description

This application drives a BLDC motor with trapezoidal waveforms
The motor runs in the sensor less mode
It runs on an ATAVRMC310 board with an ATmega32M1 part
The main source files are :

• main.c main loop
• mc_control.c PI regulation
• mc_drv.c hardware level of motor control

• mc_interface.c interface routines to motor control

• ushell_task.c command interpreter from an ascii chain
• ascii.c ascii to binary conversion

Preamble

All parameters are given for the motor included in the kit with no load.
They must be ajusted according to the application (motor, load ...)
The ramp-up sequence must be adjusted to the motor and load

Main Peripheral Use

• Timer 0 is used for speed measurement and main tick generation
• Timer 1 is used by sensor less to manage commutation delay
• PSC is used to generate PWM
• ADC is used for current and potentiometer measurement

User Manual

• At power on, the motor starts running
• The reference speed is ajusted with the potentiometer connected to the ATmega32M1 Isrc Input
• One can control the motor through Uart Interface :

Communication setting through RS232 (if PC IHM is used)

• Connect the MC310 RS232 DB9 to the PC
• Set J12 jumper on TxD
• Set J13 jumper on RxD

Communication setting through USB bridge (if PC IHM is used)

• Connect the MC310 USB connector to the PC
• Set J12 jumper on TxDUSB
• Set J13 jumper on RxDUSB

List of Material

• ATAVRMC310 (ATmega32M1 clock is 16MHz from PLL)
• ATAVRMC300 (Power Board)

Hardware Configuration

• Set the ATAVRMC300 jumpers as described in the AVR194 App Note
• Set the ATAVRMC310 jumpers as described in the AVR194 App Note

HyperTerminal Configuration

• Speed : 38400 bauds
• Bits : 8
• Stop : 1
• Handshake : None
• Parity : None

List of Commands

After reset the ATAVRMC310 board prints the welcome message and a prompt
The user commands are :

• ru : run / start the motor
• st : stop / stop the motor
• help : help / return the list of commands
• fw : forward
• bw : backward
• ss v : set speed (v is the value)
• gi : get identification / return the board id, the soft id and the soft rev
• g0 : get status 0 : return the status byte, the speed and the current
• g1 : get status 1 : return the rotation counter
  
  Note : All values are in hexadecimal form
  These commands are compatible with ATMEL Motor Control Center

Overcurrent protection

This firmware sets an overcurrent protection. The motor current is measured thanks to a shunt resistor located on the MC300 board. The amplifier 1 amplifies the shunt voltage. The output of the amplifier 1 is used as ADC input to get the motor current. The output of the amplifier 1 is also used as comparator 1 positive input. The negative output of the comparator 1 is connected to the DAC output which provides a treshold voltage for the overcurrent detection. The output of the comparator 1 is used as PSC fault input. When an overcurrent occurs, the PSC is stopped.