improvements

capture.c

@@ -1,5 +1,6 @@
 #include "capture.h"
 #include "utils/timebase.h"
+#include <math.h>
 
 uint16_t adc_measure(uint8_t channel)
 {
@@ -54,3 +55,23 @@ float measure_temp(void)
 
 	return ((80.0f / (ts_cal2 - ts_cal1)) * (ts_data - ts_cal1) + 30.0f);
 }
+
+
+void pwm2_set_frequency(float hz)
+{
+	float core_clk = 16000000 / 2.0f; // prescaller
+
+	float cnt = core_clk / hz;
+
+	uint32_t div = (uint32_t)cnt;
+
+	if (hz < 150) {
+		div /= 8;
+		TIM2_PSC = 15;
+	} else {
+		TIM2_PSC = 1;
+	}
+
+	TIM2_ARR = div; // sets frequency
+	TIM2_CCR2 = TIM2_ARR/2; // duty cycle
+}

capture.h

@@ -6,3 +6,5 @@ float measure_temp(void);
 float measure_angle(void);
 float measure_resistance(void);
 float measure_exposure(void);
+
+void pwm2_set_frequency(float hz);

init.c

@@ -141,6 +141,42 @@ void init_pwm1(void)
 }
 
 
+// pwm with variable frequency
+void init_pwm2(void)
+{
+	// enable clock for the timer
+	RCC_APB1ENR |= RCC_APB1ENR_TIM2EN;
+
+	// using timer 2, channel 2 - PA1
+	gpio_set_af(GPIOA, BIT1, AF1);
+
+	patch_register(TIM2_CCMR1, TIM_CCMR1_OC2M, TIM_OCM_PWM1); // set PWM1 mode
+
+	TIM2_CCMR1 |= TIM_CCMR1_OC2PE; // preload enable
+	TIM2_CR1 |= TIM_CR1_ARPE; // auto reload is buffered
+	TIM2_CCER |= TIM_CCER_CC2E; // enable output compare (PWM output)
+
+	patch_register(TIM2_CR1, TIM_CR1_CMS, TIM_CMS_EDGE); // centering mode
+	patch_register(TIM2_CR1, TIM_CR1_DIR, 0); // count upwards only
+
+	// frequency set to 16 kHz
+
+	/*
+	TIM2_PSC = 32; // prescaller
+	TIM2_ARR = 1000; // sets frequency
+	TIM2_CCR2 = 500; // duty cycle
+	*/
+
+	TIM2_PSC = 1; // prescaller
+	TIM2_ARR = 1600; // sets frequency
+	TIM2_CCR2 = 500; // duty cycle
+
+	// generate update event to latch the value registers
+	TIM2_EGR |= TIM_EGR_UG;
+
+	TIM2_CR1 |= TIM_CR1_CEN; // enable timer.
+}
+
 
 
 

init.h

@@ -8,3 +8,4 @@ void init_systick(void);
 void init_adc(void);
 void init_dac(void);
 void init_pwm1(void);
+void init_pwm2(void);

main.c

@@ -15,8 +15,10 @@
 static bool gate_closed = false;
 static uint32_t gate_cnt = 0;
 
-float exposure_out, exposure_accum;
-uint32_t exposure_cnt;
+static float exposure_out, exposure_accum;
+static uint32_t exposure_cnt;
+
+static uint32_t pwm2_f = 50;
 
 /** IRQ */
 void USART2_IRQHandler(void)
@@ -32,6 +34,8 @@ void USART2_IRQHandler(void)
 		// handle incoming char.
 		char c = usart_rx_char(USART2);
 
+		uint32_t pwm2_f_old = pwm2_f;
+
 		switch (c) {
 			case 'g': // nulovat pocitadlo preruseni
 				gate_cnt = 0;
@@ -53,10 +57,36 @@ void USART2_IRQHandler(void)
 				if (TIM3_CCR1 > 0) TIM3_CCR1 -= 50;
 				break;
 
+			case 'f': // zvysit PWM stridu
+				if (pwm2_f < 20000) pwm2_f += 10;
+				break;
+
+			case 's': // snizit PWM stridu
+				if (pwm2_f > 20) pwm2_f -= 10;
+				break;
+
+			case 'F': // zvysit PWM stridu
+				if (pwm2_f < 20000-100) pwm2_f += 100;
+				break;
+
+			case 'S': // snizit PWM stridu
+				if (pwm2_f > 100) {
+					pwm2_f -= 100;
+				} else {
+					pwm2_f = 20;
+				}
+
+				if (pwm2_f < 20) pwm2_f = 20;
+
+				break;
+
 			default:
 				break;
 		}
 
+		if (pwm2_f_old != pwm2_f) {
+			pwm2_set_frequency(pwm2_f);
+		}
 
 		USART2_SR ^= USART_SR_RXNE;
 	}
@@ -88,6 +118,9 @@ void SystemInit(void)
 	init_adc();
 	init_dac();
 	init_pwm1();
+	init_pwm2();
+
+	pwm2_set_frequency(50);
 
 	register_periodic_task(green_toggle, 1000); // indicate running state