nRF52 Zephyr VSCode DeviceTree

Question

Hello everyone. I've started coding with Zephyr on my nRF52 device. I'm relatively new to this. I'm trying to drive a DC motor with L298N. However, I have no idea how to configure the pin settings in the device tree. I have defined the motor pins in the device tree, but when I try to use them in main.c, I get an error saying they are not defined. Can someone help me understand how to use the device tree? Thank you.

Øivind · Accepted Answer

Try this: #include #include #include #include #include #include #include #define PWM_PERIOD_USEC 2000 static const struct gpio_dt_spec ena_dev = GPIO_DT_SPEC_GET_OR(DT_ALIAS(motor_en), gpios, {0}); static const struct gpio_dt_spec in1_dev = GPIO_DT_SPEC_GET_OR(DT_ALIAS(motor_in1), gpios, {0}); static const struct gpio_dt_spec in2_dev = GPIO_DT_SPEC_GET_OR(DT_ALIAS(motor_in2), gpios, {0}); static const struct pwm_dt_spec pwm_dev = PWM_DT_SPEC_GET(DT_ALIAS(motor_pwm0)); //#define ENA_PIN DEVICE_DT_GET(motor_en) //#define IN1_PIN DEVICE_DT_GET(motor_in1) //#define IN2_PIN DEVICE_DT_GET(motor_in2) //#define PWM_DEV PWM_DT_SPEC_GET(motor_pwm0) //#define PWM_CHANNEL DEVICE_DT_GET(motor_pwm0) #define MOTOR_SPEED_MIN -100 #define MOTOR_SPEED_MAX 100 void main(void) { //struct device *pwm_dev , *ena_dev, *in1_dev, *in2_dev; int motor_speed = 0; if (!device_is_ready(pwm_dev.dev)) { printk("Error: PWM device %s is not ready ", pwm_dev.dev->name); return; } if (!device_is_ready(ena_dev.port) || !device_is_ready(in1_dev.port) || !device_is_ready(in2_dev.port)) { printk("Error: gpio device %s is not ready ", ena_dev.port->name); return; } //pwm_dev = device_get_binding DEVICE_DT_GET(motor_pwm0); //if (!pwm_dev) { // printk("Failed to open PWM device "); // return; //} //ena_dev = device_get_binding DEVICE_DT_GET (motor_en); //in1_dev = device_get_binding DEVICE_DT_GET (motor_in1); //in2_dev = device_get_binding DEVICE_DT_GET (motor_in2); //if (!ena_dev || !in1_dev || !in2_dev) { // printk("Failed to open GPIO devices "); // return; //} if (pwm_set_dt(&pwm_dev, PWM_PERIOD_USEC, 0) < 0) { printk("Failed to configure PWM period "); return; } if (gpio_pin_configure_dt(&ena_dev, (GPIO_OUTPUT_ACTIVE | GPIO_OUTPUT)) < 0) { printk("Failed to configure ENA pin "); return; } if (gpio_pin_configure_dt(&in1_dev, (GPIO_OUTPUT_ACTIVE | GPIO_OUTPUT)) < 0) { printk("Failed to configure IN1 pin "); return; } if (gpio_pin_configure_dt(&in2_dev, (GPIO_OUTPUT_ACTIVE | GPIO_OUTPUT)) < 0) { printk("Failed to configure IN2 pin "); return; } while (1) { motor_speed = clamp(motor_speed, MOTOR_SPEED_MIN, MOTOR_SPEED_MAX); uint32_t pwm_duty = map(motor_speed, MOTOR_SPEED_MIN, MOTOR_SPEED_MAX, 0, PWM_PERIOD_USEC); if (pwm_set_dt(&pwm_dev, PWM_PERIOD_USEC, pwm_duty) < 0) { printk("Failed to set PWM duty cycle "); return; } if (motor_speed > 0) { gpio_pin_set_dt(ena_dev, 1); gpio_pin_set_dt(in1_dev, 1); gpio_pin_set_dt(in2_dev, 0); } else if (motor_speed < 0) { gpio_pin_set_dt(ena_dev, 1); gpio_pin_set_dt(in1_dev, 0); gpio_pin_set_dt(in2_dev, 1); } else { gpio_pin_set_dt(ena_dev, 0); gpio_pin_set_dt(in1_dev, 0); gpio_pin_set_dt(in2_dev, 0); } k_sleep(K_MSEC(100)); } } You can remove the commented out code and rename things as you see fit.

nRF52 Zephyr VSCode DeviceTree

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