Dimming works

Makefile

@@ -33,8 +33,7 @@ LDFLAGS = -nostdlib
 #LDFLAGS += -specs=rdimon.specs -DSEMIHOSTING
 LDFLAGS += -Wl,-Map=main.map
 #LDFLAGS += -Wl,--gc-sections 
-LIBS =
+LIBS = -lm -lgcc
-#LIBS = -lgcc
 #LIBS += -lrdimon
 
 CFLAGS += -DSTM32F103xB -DHSE_VALUE=8000000 -DLSE_VALUE=32768
@@ -42,7 +41,7 @@ CFLAGS += -DCOMPILE_TIME=$(shell date +%s) -DTARGET_DATE=$(shell date -d 'Aug 17
 
 LDFLAGS += -Tstm32_flash.ld
 CFLAGS += -I$(CMSIS_DEV_PATH)/Include -I$(CMSIS_PATH)/Include -I$(HAL_PATH)/Inc -Iconfig -Wno-unused -I../common
-#LDFLAGS += -L$(CMSIS_PATH)/Lib/GCC -larm_cortexM3l_math
+LIBS += -L$(CMSIS_PATH)/Lib/GCC -larm_cortexM3l_math
 
 ###################################################
 
@@ -61,7 +60,7 @@ cmsis_exports.c: $(CMSIS_DEV_PATH)/Include/stm32f103xb.h $(CMSIS_PATH)/Include/c
 	$(CC) -c $(CFLAGS) -o $@ $^
 #	$(CC) -E $(CFLAGS) -o $(@:.o=.pp) $^
 
-sources.tar.xz: main.c Makefile
+sources.tar.xz: main.c color.c Makefile
 	tar -caf $@ $^
 
 # don't ask...
@@ -71,7 +70,7 @@ sources.tar.xz.zip: sources.tar.xz
 sources.c: sources.tar.xz.zip
 	xxd -i $< | head -n -1 | sed 's/=/__attribute__((section(".source_tarball"))) =/' > $@
 
-main.elf: main.c startup_stm32f103xb.s system_stm32f1xx.c $(HAL_PATH)/Src/stm32f1xx_ll_utils.c base.c cmsis_exports.c
+main.elf: main.c color.c startup_stm32f103xb.s system_stm32f1xx.c $(HAL_PATH)/Src/stm32f1xx_ll_utils.c base.c cmsis_exports.c
 	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LIBS)
 	$(OBJCOPY) -O ihex $@ $(@:.elf=.hex)
 	$(OBJCOPY) -O binary $@ $(@:.elf=.bin)

color.c

@@ -0,0 +1,40 @@
+
+#include <math.h>
+
+#include "color.h"
+
+
+void hsv_to_rgb(struct hsvf *hsv, struct rgbf *rgb) {
+    float h = hsv->h, s = hsv->s, v = hsv->v;
+    float c = v * s; // Chroma
+    float hmod = fmodf(h * 6.0f, 6.0f);
+    float x = c * (1.0f - fabsf(fmodf(hmod, 2.0f) - 1.0f));
+    float m = v - c;
+
+    switch ((int)hmod) {
+        case 0:
+            rgb->r = c; rgb->g = x; rgb->b = 0;
+            break;
+        case 1:
+            rgb->r = x; rgb->g = c; rgb->b = 0;
+            break;
+        case 2:
+            rgb->r = 0; rgb->g = c; rgb->b = x;
+            break;
+        case 3:
+            rgb->r = 0; rgb->g = x; rgb->b = c;
+            break;
+        case 4:
+            rgb->r = x; rgb->g = 0; rgb->b = c;
+            break;
+        case 5:
+            rgb->r = c; rgb->g = 0; rgb->b = x;
+            break;
+        default:
+            rgb->r = 0; rgb->g = 0; rgb->b = 0;
+    }
+
+    rgb->r += m;
+    rgb->g += m;
+    rgb->b += m;
+}

color.h

@@ -0,0 +1,14 @@
+#ifndef __COLOR_H__
+#define __COLOR_H__
+
+struct hsvf {
+    float h, s, v;
+};
+
+struct rgbf {
+    float r, g, b;
+};
+
+void hsv_to_rgb(struct hsvf *hsv_in, struct rgbf *rgb_out);
+
+#endif /* __COLOR_H__ */

main.c

@@ -16,6 +16,18 @@
  */
 
 #include "global.h"
+#include "math.h"
+#include "color.h"
+
+static struct hsvf g_color_s = {0.0f, 0.0f, 0.0f};
+struct hsvf *g_color = &g_color_s;
+volatile uint64_t g_time_ms = 0;
+
+uint64_t wait_until(uint64_t timestamp);
+bool check_interval(uint64_t *timestamp, uint64_t interval);
+void blink_led(uint64_t *ts, int t_on, int t_off, GPIO_TypeDef *gpio, int pin);
+
+void update_timers(struct rgbf *rgb);
 
 uint32_t pcg32_random_r() {
     // *Really* minimal PCG32 code / (c) 2014 M.E. O'Neill / pcg-random.org
@@ -34,39 +46,28 @@ uint32_t pcg32_random_r() {
 int main(void){
     /* We're starting out from HSI@8MHz */
     SystemCoreClockUpdate();
-    SCB->SCR &= (~SCB_SCR_SLEEPONEXIT_Msk) & (~SCB_SCR_SLEEPDEEP_Msk); /* Disable for now */
+    SysTick_Config(SystemCoreClock / 1000); /* 1ms tick */
-    for (int i=0; i<50000; i++)
-        asm volatile ("nop");
 
     /* Turn on lots of neat things */
-    RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_AFIOEN;
+    RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_AFIOEN | RCC_APB2ENR_TIM1EN;
     RCC->APB1ENR |= RCC_APB1ENR_TIM3EN | RCC_APB1ENR_TIM4EN;
 
     GPIOC->CRH |=
           (0<<GPIO_CRH_CNF13_Pos) | (2<<GPIO_CRH_MODE13_Pos); /* PC13 - LED */
     GPIOB->CRL |=
-          (2<<GPIO_CRL_CNF5_Pos) | (2<<GPIO_CRL_MODE5_Pos); /* PB5 - TIM3_CH2 */
+          (2<<GPIO_CRL_CNF5_Pos) | (2<<GPIO_CRL_MODE5_Pos); /* PB5 - TIM3_CH2 (r fractional) */
     AFIO->MAPR |= (2 << AFIO_MAPR_TIM3_REMAP_Pos); /* Map TIM3_CH2 to PB5 */
     GPIOB->CRH |=
-          (2<<GPIO_CRH_CNF8_Pos) | (2<<GPIO_CRH_MODE8_Pos)  /* PB8 - TIM4_CH3 */
+          (2<<GPIO_CRH_CNF8_Pos) | (2<<GPIO_CRH_MODE8_Pos)  /* PB8 - TIM4_CH3 (g fractional) */
-        | (2<<GPIO_CRH_CNF9_Pos) | (2<<GPIO_CRH_MODE9_Pos); /* PB9 - TIM4_CH4 */
+        | (2<<GPIO_CRH_CNF9_Pos) | (2<<GPIO_CRH_MODE9_Pos); /* PB9 - TIM4_CH4 (b fractional) */
     GPIOC->ODR |= 1<<13; /* LED */
 
-    TIM3->SMCR = (3<<TIM_SMCR_TS_Pos) | (6 << TIM_SMCR_SMS_Pos);
+    GPIOA->CRH = (2<<GPIO_CRH_CNF8_Pos) | (2<<GPIO_CRH_MODE8_Pos); /* PA8 - TIM1_CH1 (global dimming) */
+
+
+    TIM3->SMCR = (3<<TIM_SMCR_TS_Pos) | (4 << TIM_SMCR_SMS_Pos);
     TIM4->CR2 = (4<<TIM_CR2_MMS_Pos);
 
-    int period = 0xffff;
-    int thr[3] = {20000, 30000};
-
-    int overlap = 1000;
-
-    TIM4->CCR3 = thr[0];
-    TIM4->CCR4 = thr[1];
-    TIM4->CCR1 = thr[0];
-    TIM3->CCR2 = thr[1] - thr[0];
-    TIM3->ARR = 0xfffe;
-    TIM4->ARR = 0xffff;
-
     TIM3->CCER = TIM_CCER_CC2E;
     TIM3->CCMR1 = (0<<TIM_CCMR1_CC2S_Pos) | TIM_CCMR1_OC2PE | (6<<TIM_CCMR1_OC2M_Pos);
     TIM4->CCER = TIM_CCER_CC3E | TIM_CCER_CC4E | TIM_CCER_CC1E | TIM_CCER_CC3P | TIM_CCER_CC4P;
@@ -74,13 +75,59 @@ int main(void){
     TIM4->CCMR2 = (0<<TIM_CCMR2_CC4S_Pos) | TIM_CCMR2_OC4PE | (6<<TIM_CCMR2_OC4M_Pos) \
                 | (0<<TIM_CCMR2_CC3S_Pos) | TIM_CCMR2_OC3PE | (7<<TIM_CCMR2_OC3M_Pos);
 
-    TIM3->CR1 = TIM_CR1_ARPE | TIM_CR1_OPM | TIM_CR1_OPM;
+    TIM3->CR1 = TIM_CR1_ARPE | TIM_CR1_CEN;
+    TIM4->CR1 = TIM_CR1_ARPE | TIM_CR1_CEN;
     TIM4->CR1 = TIM_CR1_ARPE | TIM_CR1_CEN;
 
+    TIM1->CCMR1 = (0<<TIM_CCMR1_CC1S_Pos) | TIM_CCMR1_OC1PE | (6<<TIM_CCMR1_OC1M_Pos);
+    TIM1->SMCR = (3 << TIM_SMCR_TS_Pos) | (4 << TIM_SMCR_SMS_Pos);
+    TIM1->CCER = TIM_CCER_CC1E;
+    TIM1->ARR = 0xffff;
+    TIM1->BDTR = TIM_BDTR_MOE;
+    TIM1->CR1 = TIM_CR1_ARPE | TIM_CR1_CEN;
+
+    uint64_t ts = g_time_ms;
+    uint64_t led_ts = 0;
     for (;;) {
+        g_color->h = fmodf(g_color->h + 0.0005, 1.0f);
+        //g_color->h = 0.0;
+        g_color->s = 0.8;
+        g_color->v = 1.0;
+
+        struct rgbf rgb;
+        hsv_to_rgb(g_color, &rgb);
+        update_timers(&rgb);
+
+        ts = wait_until(ts + 5);
+
+        blink_led(&led_ts, 100, 200, GPIOC, 13);
     }
 }
 
+void update_timers(struct rgbf *rgb) {
+    float gamma = 2.2f;
+    rgb->r = powf(rgb->r, gamma);
+    rgb->g = powf(rgb->g, gamma);
+    rgb->b = powf(rgb->b, gamma);
+
+    float total = rgb->r + rgb->g + rgb->b;
+    rgb->r /= total;
+    rgb->g /= total;
+    rgb->b /= total;
+
+    float period = 0xffff;
+    int thr[2] = {roundf(period * rgb->r), roundf(period * (rgb->r + rgb->g))};
+
+    TIM4->CCR3 = thr[0];
+    TIM4->CCR4 = thr[1];
+    TIM4->CCR1 = thr[0];
+    TIM3->CCR2 = thr[1] - thr[0];
+    TIM3->ARR  = period;
+    TIM4->ARR  = period;
+
+    TIM1->CCR1 = roundf((period - 1) * total / 3.0f);
+}
+
 void gdb_dump(void) {
     /* debugger hook */
 }
@@ -104,6 +151,37 @@ void PendSV_Handler(void) {
 }
 
 void SysTick_Handler(void) {
-    asm volatile ("bkpt");
+    g_time_ms ++;
+}
+
+uint64_t wait_until(uint64_t timestamp) {
+    while (g_time_ms < timestamp)
+        ;
+    return g_time_ms;
+}
+
+bool check_interval(uint64_t *timestamp, uint64_t interval) {
+    if (*timestamp == 0) {
+        *timestamp = g_time_ms;
+        return false;
+    }
+
+    if (g_time_ms < *timestamp + interval)
+        return false;
+
+    *timestamp = g_time_ms;
+    return true;
+}
+
+void blink_led(uint64_t *ts, int t_on, int t_off, GPIO_TypeDef *gpio, int pin) {
+    int bm = 1<<pin;
+    if (gpio->ODR & bm) {
+        if (check_interval(ts, t_off))
+            gpio->BRR = bm;
+
+    } else {
+        if (check_interval(ts, t_on))
+            gpio->BSRR = bm;
+    }
 }