Added software PWM and deleted Debug folder

fw/Core/Inc/led.h

@@ -0,0 +1,48 @@
+/*
+ * led.h
+ *
+ *  Created on: Jun 6, 2021
+ *      Author: user
+ */
+
+#ifndef INC_LED_H_
+#define INC_LED_H_
+
+#include "stdint.h"
+#include "stm32l0xx_hal.h"
+#include "stm32l0xx_ll_gpio.h"
+
+/*
+ * Context struct
+ */
+
+typedef struct {
+	GPIO_TypeDef *red_led_port;
+	int red_led_pin;
+	GPIO_TypeDef *green_led_port;
+	int green_led_pin;
+	GPIO_TypeDef *blue_led_port;
+	int blue_led_pin;
+
+} led_context_t;
+
+/*
+ * Externally defined variables
+ */
+
+extern int led_pwm_max;
+extern int led_pwm_counter;
+extern int led_red_intensity;
+extern int led_green_intensity;
+extern int led_blue_intensity;
+
+/*
+ * Function prototypes
+ */
+
+void led_set_color(uint8_t red, uint8_t green, uint8_t blue);
+void led_off();
+void led_pwm_handler();
+void led_init(led_context_t *context, int pwm_freq, int pwm_handler_freq);
+
+#endif /* INC_LED_H_ */

fw/Core/Inc/main.h

@@ -44,6 +44,7 @@ extern "C" {
 
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
+#include "led.h"
 /* USER CODE END Includes */
 
 /* Exported types ------------------------------------------------------------*/

fw/Core/Src/led.c

@@ -0,0 +1,121 @@
+/*
+ * led.c
+ *
+ *  Created on: Jun 6, 2021
+ *      Author: user
+ */
+
+#include "led.h"
+
+/*
+ * Global variables
+ */
+
+int led_pwm_max;
+int led_pwm_counter;
+int led_red_intensity;
+int led_green_intensity;
+int led_blue_intensity;
+int led_red_state;
+int led_green_state;
+int led_blue_state;
+led_context_t *led_context = NULL;
+
+/*
+ * Functions
+ */
+
+/*
+ * led_set_color():
+ * Set LED color
+ * Arguments:
+ *     uint8_t red: red color intensity, possible values 0 ... 255
+ *     uint8_t green: green color intensity, possible values 0 ... 255
+ *     uint8_t blue: blue color intensity, possible values 0 ... 255
+ * NOTE: if (color * led_pwm_max) < 255, LED will be off
+ */
+void led_set_color(uint8_t red, uint8_t green, uint8_t blue)
+{
+	led_red_intensity = (int)red * led_pwm_max / 255;
+	led_green_intensity = (int)green * led_pwm_max / 255;
+	led_blue_intensity = (int)blue * led_pwm_max / 255;
+}
+
+/*
+ * led_off():
+ * Set LED intensity to 0 for each color
+ */
+void led_off()
+{
+	led_red_intensity = 0;
+	led_green_intensity = 0;
+	led_blue_intensity = 0;
+}
+
+/*
+ * led_pwm_handler():
+ * handles switching LEDs on/off according to desired intensity;
+ * should be regularly called in timer routine, preferably in SysTick_Handler()
+ */
+void led_pwm_handler()
+{
+	int new_red_state, new_green_state, new_blue_state;
+
+	if (led_context == NULL) {
+		// led_pwm_handler() may be called before led_init() was called;
+		// this would result in a crash
+		return;
+	}
+
+	new_red_state = led_pwm_counter >= led_red_intensity ? 1 : 0;
+	new_green_state = led_pwm_counter >= led_green_intensity ? 1 : 0;
+	new_blue_state = led_pwm_counter >= led_blue_intensity ? 1 : 0;
+	// SysTick() is called at 1 kHz frequency, we don't want to call HAL_GPIO_WritePin() every time
+	if (led_red_state != new_red_state) {
+		LL_GPIO_TogglePin(led_context->red_led_port, led_context->red_led_pin);
+		led_red_state = new_red_state;
+	}
+	if (led_green_state != new_green_state) {
+		LL_GPIO_TogglePin(led_context->green_led_port, led_context->green_led_pin);
+		led_green_state = new_green_state;
+	}
+	if (led_blue_state != new_blue_state) {
+		LL_GPIO_TogglePin(led_context->blue_led_port, led_context->blue_led_pin);
+		led_blue_state = new_blue_state;
+	}
+	if (++led_pwm_counter >= led_pwm_max) {
+		led_pwm_counter = 0;
+	}
+}
+
+/*
+ * led_init():
+ * Saves context and calculates max pwm value. Note that is PWM frequency is low (< 25 Hz),
+ * flickering might be visible. If pwm_handler_freq is low (less than several kHz),
+ * resolution of PWM will be limited
+ * Arguments:
+ *     led_context_t *context:
+ *         Pointer to LED context struct, which contains port and pin for each LED
+ *     int pwm_freq:
+ *         Desired frequency of PWM in Hz (e.g. 25 Hz)
+ *     int pwm_handler_freq:
+ *         Frequency of led_pwm_handler() calls. Eequal to timer frequency if timer callback is used,
+ *         e.g. if led_pwm_handler() is called within SysTick_Handler(), then frequency is
+ *         HAL_TICK_FREQ_1KHZ
+ */
+void led_init(led_context_t *context, int pwm_freq, int pwm_handler_freq)
+{
+	// save context
+	led_context = context;
+	// Initial values
+	led_red_intensity = 0;
+	led_red_state = 1; // state is inverted (LEDs are sinking current into MCU)
+	led_green_intensity = 0;
+	led_green_state = 1;
+	led_blue_intensity = 0;
+	led_blue_state = 1;
+	// calculate PWM counter overflow value (max value)
+	// e.g. for 1 kHz handler freq and 25 Hz PWM freq, we only have
+	// resolution of 40 steps for pwm
+	led_pwm_max = pwm_handler_freq / pwm_freq;
+}

fw/Core/Src/main.c

@@ -94,6 +94,16 @@ int main(void)
   /* USER CODE BEGIN 2 */
   LL_I2C_Enable(I2C1);
   LL_LPUART_Enable(LPUART1);
+  /* LED PWM context */
+  led_context_t led_context;
+  led_context.red_led_port = LED_R_GPIO_Port;
+  led_context.green_led_port = LED_G_GPIO_Port;
+  led_context.blue_led_port = LED_B_GPIO_Port;
+  led_context.red_led_pin = LED_R_Pin;
+  led_context.green_led_pin = LED_G_Pin;
+  led_context.blue_led_pin = LED_B_Pin;
+  led_init(&led_context, 50, 1000);
+  led_set_color(0, 20, 0);
   /* USER CODE END 2 */
 
   /* Infinite loop */

fw/Core/Src/stm32l0xx_it.c

@@ -23,6 +23,7 @@
 #include "stm32l0xx_it.h"
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
+#include "led.h"
 /* USER CODE END Includes */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -130,6 +131,7 @@ void SysTick_Handler(void)
   /* USER CODE END SysTick_IRQn 0 */
   HAL_IncTick();
   /* USER CODE BEGIN SysTick_IRQn 1 */
+  led_pwm_handler();
   /* USER CODE END SysTick_IRQn 1 */
 }