STM32F446 CNC Motion Controller Design

Thought for 5 sec

flux

Yes.

You can view the work directly in Flux here:

Project:
/customsolutions/stm32f446-cnc-laser-controller

Where to look:

PCB / Layout view — see the updated 120 × 120 mm, 4-layer placement
Schematic view — see the STM32F446 CNC controller schematic
Files tab — open:
- Proof of Layout Work — 120 mm 4-Layer Update
- Design Notes — Routing and Manufacturing
- Firmware Starter STM32F446 CNC Laser Controller

You can inspect the board, zoom around, check parts, then return to this chat and continue from here.

customsolutions

Open the PCB layout and point me to the placement view.

Thought for 4 sec

flux

I can’t directly open the Flux UI for you, but here’s exactly where to go:

Open the project:
/customsolutions/stm32f446-cnc-laser-controller
In the left/top project navigation, select PCB or Layout view.
Once in the PCB layout:
- Zoom out to see the full 120 mm × 120 mm board.
- The STM32 MCU U1 should be near the center.
- USB connector J1 should be on the left edge.
- Limit/input header J6 should also be on the left edge.
- Motion output header J5 should be on the right-side area.
- Power section parts F1, U2, L1, D3, C11/C12 should be in the upper-right area.
To verify the saved proof file, open the Files tab and select:
Proof of Layout Work — 120 mm 4-Layer Update

After you inspect the layout, come back here and we can either adjust placement or start a fresh routing pass.

Optimize placement

Run layout DRC

Check board size

Review power placement

Refine this doc

Ask about this doc

Firmware Starter — STM32F446 CNC / Laser Controller

Platform & Toolchain

MCU: STM32F446RET6 / STM32F446RETx LQFP64
Recommended framework: STM32 HAL using STM32CubeIDE or PlatformIO STM32Cube framework
Firmware target concept: grblHAL-style CNC motion controller bring-up

Pin Mapping

Table

Function	Requested Pin	Implemented Pin	Notes
X_STEP	PA0	PA0	Buffered to 5V output header
X_DIR	PA1	PA1	Buffered
X_EN	PA2	PA2	Buffered
Y_STEP	PA3	PA3	Buffered
Y_DIR	PA4	PA4	Buffered
Y_EN	PA5	PA5	Buffered
Z_STEP	PA6	PA6	Buffered
Z_DIR	PA7	PA7	Buffered
Z_EN	PB0	PB0	Buffered via second buffer
LIMIT_X	PB1	PB1	10k pull-up + RC filter
LIMIT_Y	PB2	PB2	10k pull-up + RC filter
LIMIT_Z	PB10	PB10	10k pull-up + RC filter
ESTOP	PB11	PC6	PB11 is not present on the STM32F446RE LQFP64 symbol used in this project
FEED_HOLD	PB12	PB12	10k pull-up + RC filter
CYCLE_START	PB13	PB13	10k pull-up + RC filter
PROBE	PB14	PB14	10k pull-up + RC filter
SPINDLE_PWM	PA8	PA8 TIM1_CH1	Buffered output
COOLANT	PB15	PB15	Buffered output
UART_TX	PA9	PA9	Debug UART header
UART_RX	PA10	PA10	Debug UART header
USB_DM	PA11	PA11	22Ω series + ESD
USB_DP	PA12	PA12	22Ω series + ESD
SWDIO	PA13	PA13	SWD header
SWCLK	PA14	PA14	SWD header
I2C_SCL	PB6	PB6	4.7k pull-up
I2C_SDA	PB7	PB7	4.7k pull-up

PlatformIO Example

Ini
[env:stm32f446re]
platform = ststm32
board = nucleo_f446re
framework = stm32cube
upload_protocol = stlink
monitor_speed = 115200

HAL Bring-Up Skeleton

C
#include "main.h"

#define X_STEP_GPIO GPIOA
#define X_STEP_PIN  GPIO_PIN_0
#define X_DIR_GPIO  GPIOA
#define X_DIR_PIN   GPIO_PIN_1
#define X_EN_GPIO   GPIOA
#define X_EN_PIN    GPIO_PIN_2
#define Y_STEP_GPIO GPIOA
#define Y_STEP_PIN  GPIO_PIN_3
#define Y_DIR_GPIO  GPIOA
#define Y_DIR_PIN   GPIO_PIN_4
#define Y_EN_GPIO   GPIOA
#define Y_EN_PIN    GPIO_PIN_5
#define Z_STEP_GPIO GPIOA
#define Z_STEP_PIN  GPIO_PIN_6
#define Z_DIR_GPIO  GPIOA
#define Z_DIR_PIN   GPIO_PIN_7
#define Z_EN_GPIO   GPIOB
#define Z_EN_PIN    GPIO_PIN_0

#define LIMIT_X_GPIO GPIOB
#define LIMIT_X_PIN  GPIO_PIN_1
#define LIMIT_Y_GPIO GPIOB
#define LIMIT_Y_PIN  GPIO_PIN_2
#define LIMIT_Z_GPIO GPIOB
#define LIMIT_Z_PIN  GPIO_PIN_10
#define ESTOP_GPIO   GPIOC
#define ESTOP_PIN    GPIO_PIN_6
#define FEED_GPIO    GPIOB
#define FEED_PIN     GPIO_PIN_12
#define CYCLE_GPIO   GPIOB
#define CYCLE_PIN    GPIO_PIN_13
#define PROBE_GPIO   GPIOB
#define PROBE_PIN    GPIO_PIN_14
#define COOLANT_GPIO GPIOB
#define COOLANT_PIN  GPIO_PIN_15

TIM_HandleTypeDef htim1;
UART_HandleTypeDef huart1;
I2C_HandleTypeDef hi2c1;

static void MX_GPIO_Init(void) {
    __HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();
    __HAL_RCC_GPIOC_CLK_ENABLE();

    GPIO_InitTypeDef g = {0};
    g.Mode = GPIO_MODE_OUTPUT_PP;
    g.Pull = GPIO_NOPULL;
    g.Speed = GPIO_SPEED_FREQ_HIGH;
    g.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7;
    HAL_GPIO_Init(GPIOA, &g);

    g.Pin = GPIO_PIN_0|GPIO_PIN_15;
    HAL_GPIO_Init(GPIOB, &g);

    g.Mode = GPIO_MODE_INPUT;
    g.Pull = GPIO_NOPULL; // external pull-ups and RC filters are fitted
    g.Speed = GPIO_SPEED_FREQ_LOW;
    g.Pin = GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_10|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14;
    HAL_GPIO_Init(GPIOB, &g);
    g.Pin = GPIO_PIN_6;
    HAL_GPIO_Init(GPIOC, &g);
}

static void MX_TIM1_Init(void) {
    __HAL_RCC_TIM1_CLK_ENABLE();
    htim1.Instance = TIM1;
    htim1.Init.Prescaler = 0;
    htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim1.Init.Period = 999; // PWM frequency = timer_clk / 1000
    htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    HAL_TIM_PWM_Init(&htim1);

    TIM_OC_InitTypeDef oc = {0};
    oc.OCMode = TIM_OCMODE_PWM1;
    oc.Pulse = 0;
    oc.OCPolarity = TIM_OCPOLARITY_HIGH;
    HAL_TIM_PWM_ConfigChannel(&htim1, &oc, TIM_CHANNEL_1);
    HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
}

static inline void spindle_set_pwm_permille(uint16_t duty) {
    if (duty > 1000) duty = 1000;
    __HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, duty);
}

int main(void) {
    HAL_Init();
    SystemClock_Config(); // configure HSE=8MHz and PLL for USB-capable clock tree in CubeMX
    MX_GPIO_Init();
    MX_TIM1_Init();

    while (1) {
        GPIO_PinState estop = HAL_GPIO_ReadPin(ESTOP_GPIO, ESTOP_PIN);
        if (estop == GPIO_PIN_RESET) {
            spindle_set_pwm_permille(0);
            HAL_GPIO_WritePin(COOLANT_GPIO, COOLANT_PIN, GPIO_PIN_RESET);
        }
        HAL_Delay(1);
    }
}

Bring-Up Notes

Configure HSE as 8MHz crystal in CubeMX and verify the USB FS 48MHz clock source.
Confirm ESTOP firmware pin mapping as PC6 unless the MCU package or pinout is changed.
Validate output polarity with the selected external stepper drivers before enabling machine motion.

Platform & Toolchain
Pin Mapping
PlatformIO Example
HAL Bring-Up Skeleton
Bring-Up Notes

Reviews

Documents

Project Specification — STM32F446 CNC / Laser Motion Controller

Firmware Starter — STM32F446 CNC / Laser Controller

Design Notes — Routing and Manufacturing

Proof of Layout Work — 120 mm 4-Layer Update

Assets

No assets added.

Project Name

STM32F446 CNC Laser Controller

Description

Professional 3-axis STM32F446 CNC/laser motion controller for grblHAL-class firmware, with 24V input power, protected 5V/3.3V rails, USB, SWD, buffered motion outputs, filtered inputs, and a 100mm x 100mm 2-layer PCB target.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor	Qty 1
Arrow	$9.30–$12.96
Digi-Key	$19.53–$21.99
HQonline	$13.10–$13.45
LCSC	$13.38–$13.88
Mouser	$22.70–$22.76
TME	$13.79
Verical	$9.23–$20.78

Controls

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