From: Martin Mares <mj@ucw.cz>
Date: Tue, 9 Jul 2019 19:07:15 +0000 (+0200)
Subject: Test: PWM control
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=199f1c986955517d264fb8457041002911aba0e7;p=home-hw.git

Test: PWM control
---

diff --git a/test-opencm3/test.c b/test-opencm3/test.c
index e49bce7..b4e9e70 100644
--- a/test-opencm3/test.c
+++ b/test-opencm3/test.c
@@ -5,6 +5,7 @@
 #include <libopencm3/cm3/systick.h>
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/timer.h>
 #include <libopencm3/stm32/usart.h>
 
 static void clock_setup(void)
@@ -12,9 +13,11 @@ static void clock_setup(void)
 	rcc_clock_setup_in_hse_8mhz_out_72mhz();
 
 	rcc_periph_clock_enable(RCC_GPIOA);
+	rcc_periph_clock_enable(RCC_GPIOB);
 	rcc_periph_clock_enable(RCC_GPIOC);
 	rcc_periph_clock_enable(RCC_USART1);
 	rcc_periph_clock_enable(RCC_TIM3);
+	rcc_periph_clock_enable(RCC_TIM4);
 	rcc_periph_clock_enable(RCC_DMA1);
 }
 
@@ -69,6 +72,7 @@ static void usart_setup(void)
 }
 
 static bool bypass_active;
+static byte pwm;
 
 static void show_temperature(void)
 {
@@ -81,17 +85,46 @@ static void show_temperature(void)
 		else
 			debug_printf("%3d.%03d", t / 1000, t % 1000);
 	}
-	debug_putc(' ');
-	debug_putc('0' + bypass_active);
+	debug_printf(" %d", bypass_active);
+	debug_printf(" %d", pwm);
 	debug_puts("\r\n");
 }
 
+static void pwm_init(void)
+{
+	timer_set_prescaler(TIM4, 3);	// clock = 72 MHz / 2 = 36 MHz
+	timer_set_mode(TIM4, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
+	timer_disable_preload(TIM4);
+	timer_set_period(TIM4, 255);	// PWM frequency = 18 MHz / 256 = 70.3125 kHz	FIXME
+	timer_set_oc_mode(TIM4, TIM_OC1, TIM_OCM_PWM1);
+	timer_set_oc_value(TIM4, TIM_OC1, 1);
+	pwm = 1;
+	/*
+	 *	1	0.03
+	 *	4	0.48
+	 *	8	1.54
+	 *	12	2.71
+	 *	16	3.99
+	 *	24	6.34
+	 *	32	7.85
+	 *	64	7.95
+	 *	128	8.02
+	 *	255	
+	 */
+	timer_set_oc_polarity_high(TIM4, TIM_OC1);
+	timer_enable_counter(TIM4);
+	timer_enable_oc_output(TIM4, TIM_OC1);
+
+	gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO6);
+}
+
 int main(void)
 {
 	clock_setup();
 	gpio_setup();
 	tick_setup();
 	usart_setup();
+	pwm_init();
 
 	ds_init();
 
@@ -110,6 +143,24 @@ int main(void)
 				bypass_active = 0;
 				gpio_clear(GPIOC, GPIO15);	// opto-coupler
 				gpio_set(GPIOC, GPIO14);	// LED
+			} else if (ch >= '0' && ch <= '9') {
+				pwm = 3*(ch - '0') + 1;
+				/*
+				 *	ch	pwm	  %
+				 *	0	  1	  0
+				 *	1	  4	  0
+				 *	2	  7	 18
+				 *	3	 10	 31
+				 *	4	 13	 44
+				 *	5	 16	 57
+				 *	6	 19	 71
+				 *	7	 22	 84
+				 *	8	 25	 97
+				 *	9	 28	100
+				 *
+				 *	% = pwm*4.389 - 12.723
+				 */
+				timer_set_oc_value(TIM4, TIM_OC1, pwm);
 			}
 		}
 		if (cycles++ >= 50) {