By: Team Short Circuit; Motor Drive By: Team Short Circuit; Leader: Miranda Gumbert Hardware Specialist: George Tittnich Software Specialist: Jordan Shawley Assistant: Patrick Tunney

Overview Understanding the Problem Hardware Registers Used Components Needed Pololu 1212 MC33926 Wiring Registers Used Software Implementation Summary References Q&A

The Problem Drive and Control the Motor Being able to make it go from stopped to full speed

Components Needed 32 bit ColdFire MCU FireBird32 Smart Car chassis with mounted brushed motor Pololu 1212 ***Make sure to raise your car using your parts box***

Hardware

Pololu 1212 Specs Operating Voltage: 5V-28V Operating Current: 3A-5A Overheating Issues: Thermal Tape Heat Sink MC33926 – Throttle Control H-Bridge

MC33926 Pin Description

Wiring Power Supply MCU PTE3 Motor

Registers Used TPM1CnSC TPM1CnV TPM1C1SC_ELSnx

Registers Used

Software Design Initialize motorDC as global variable Set up ADC for PWM Divide Result for values 0-100 Use the potentiometer to adjust speed Convert values to ticks and update Channel 1

Software Interrupt VectorNumber_Vtpm1ch1 void MotorISR(void) { int mSeconds = 1000; PTED_PTED6 = 1; //SPSclk TPM1C1SC & = 0x7F; //AND to extract bit if(motorB) //PTED_PTED3 //convert to microseconds mSeconds = motorDC*10; //1ms= 1000 microseconds else mSeconds = (100 – motorDC)*10; } TPM1C1V += 3 * mSeconds; //update PTED_PTED6 = 0; //update

Additional Tips Setting constraints Addressing 2 special cases: 0% 100%

Figure 1: Duty Cycle at 26% Figure 2: Duty Cycle at 76%

Summary Use the Pololu 1212 to run the mounted brushed motor using PWM control Use the potentiometer to change the duty cycle Be sure to prop up the car prior to operation Be sure to account for 0% and 100% duty cycle

References "MC33926 Motor Driver Carrier." MC33926 Motor Driver Carrier (n.d.): n. pag. Web. 24 Feb. 2015. Semiconductor, Inc. Freescale. "5.0 A Throttle Control H-Bridge." MC33926, 5.0 A Throttle Control H-Bridge (n.d.): n. pag. 5.0 A Throttle Control H-Bridge. Web. 24 Feb. 2015. Sumey, Jeff. "Jeff Sumey's Virtual Resource Center." Jeff Sumey's Virtual Resource Center. Jeff Sumey, n.d. Web. 24 Feb. 2015.

Questions?