How Your Code Actually Spins a Motor (STM32 Registers to BLDC)

#STM32 #EmbeddedSystems #BLDC #Microcontroller #MotorControl #Firmware #Electronics How does one line of C code end up spinning a motor? We follow a single register write on an STM32 all the way down: from the CPU, through the timer, the gate driver and the MOSFETs, to the current flowing in a BLDC motor's coils. We start by turning on an LED with STM32 HAL, open up HAL_GPIO_WritePin, and replace it with a direct write to the BSRR register. From there we cover memory-mapped I/O and the STM32F767 memory map, peripheral clocks in RCC, reading three Hall sensors through the GPIO IDR register, six-step commutation in a switch statement, center-aligned PWM from TIM1 at 20 kHz, complementary outputs, dead time and the MOE bit in BDTR, the gate driver and three-phase inverter, what the CPU and bus actually do with a store instruction, and finally closed-loop motor speed control with a PI controller. Every line of code in this video is real firmware running on an STM32F767 BLDC motor-control lab board. Chapters 00:00 One line of code, one spinning motor 00:24 Turning on an LED with STM32 HAL 00:56 Inside HAL_GPIO_WritePin: the BSRR register 01:34 Skipping HAL: writing the register directly 01:47 GPIOC is just an address (volatile pointer) 02:16 STM32 memory map and memory-mapped I/O 02:57 Enabling peripheral clocks (RCC) 03:27 How a BLDC motor turns 04:14 Reading Hall sensors: IDR and HallSum 05:49 Six-step commutation in code (CCR, CCER) 06:53 PWM and the timer: 20 kHz center-aligned 08:04 Complementary outputs, dead time and MOE 08:57 Gate driver and three-phase inverter 10:11 MOSFETs, gate driver choice and PCB layout 10:31 The full loop, start to finish 11:03 What happens inside the MCU when you write an address 12:02 Closed-loop speed control with a PI controller 12:53 Building a BLDC motor controller from scratch (course) 14:39 Wrap-up: how far one line goes