Sorta does something

.clang-format

@@ -1,6 +1,6 @@
 # Generated from CLion C/C++ Code Style settings
 BasedOnStyle: LLVM
-AccessModifierOffset: -2
+AccessModifierOffset: 0
 AlignAfterOpenBracket: Align
 AlignConsecutiveAssignments: None
 AlignOperands: Align
@@ -38,7 +38,7 @@ CompactNamespaces: false
 ContinuationIndentWidth: 8
 IndentCaseLabels: true
 IndentPPDirectives: None
-IndentWidth: 2
+IndentWidth: 4
 KeepEmptyLinesAtTheStartOfBlocks: true
 MaxEmptyLinesToKeep: 2
 NamespaceIndentation: All
@@ -63,4 +63,4 @@ SpacesInContainerLiterals: false
 SpacesInParentheses: false
 SpacesInSquareBrackets: false
 TabWidth: 4
-UseTab: ForContinuationAndIndentation
+UseTab: Always

RTT/SEGGER_RTT_Conf.h

@@ -75,7 +75,7 @@ Revision: $Rev: 21386 $
 // Up-channel 1: SystemView
 //
 #ifndef   SEGGER_RTT_MAX_NUM_UP_BUFFERS
-  #define SEGGER_RTT_MAX_NUM_UP_BUFFERS             (3)     // Max. number of up-buffers (T->H) available on this target    (Default: 3)
+  #define SEGGER_RTT_MAX_NUM_UP_BUFFERS             (1)     // Max. number of up-buffers (T->H) available on this target    (Default: 3)
 #endif
 //
 // Most common case:
@@ -83,11 +83,11 @@ Revision: $Rev: 21386 $
 // Down-channel 1: SystemView
 //
 #ifndef   SEGGER_RTT_MAX_NUM_DOWN_BUFFERS
-  #define SEGGER_RTT_MAX_NUM_DOWN_BUFFERS           (3)     // Max. number of down-buffers (H->T) available on this target  (Default: 3)
+  #define SEGGER_RTT_MAX_NUM_DOWN_BUFFERS           (1)     // Max. number of down-buffers (H->T) available on this target  (Default: 3)
 #endif
 
 #ifndef   BUFFER_SIZE_UP
-  #define BUFFER_SIZE_UP                            (1024)  // Size of the buffer for terminal output of target, up to host (Default: 1k)
+  #define BUFFER_SIZE_UP                            (128)  // Size of the buffer for terminal output of target, up to host (Default: 1k)
 #endif
 
 #ifndef   BUFFER_SIZE_DOWN

main.c

@@ -17,6 +17,8 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdio.h>
+
 #include <libopencm3/cm3/nvic.h>
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/gpio.h>
@@ -24,6 +26,23 @@
 
 #include <SEGGER_RTT.h>
 
+#define DHT_PORT GPIOB
+#define DHT_PIN  GPIO0
+
+enum DHT11_STATE {
+	DHT11_STOP,  // Stop statemachine
+	DHT11_BEGIN_START,  // We drive DATA Low for min 18ms
+	DHT11_END_START,  // We drive DATA High and set it to input
+	DHT11_RESPONSE,  // Wait for DHT to drive DATA Low
+	DHT11_DATA,
+	DHT11_END
+};
+
+int g_dht11_state = DHT11_STOP;
+
+int g_dht_i = 0;
+uint16_t g_dht_vals[100] = {0};
+
 static void delay(int count)
 {
 	for (int i=0; i < count; i++) {
@@ -44,7 +63,7 @@ static void gpio_setup(void)
 	// GPIOA_CRH = (GPIO_CNF_OUTPUT_PUSHPULL << (((5 - 8) * 4) + 2));
 	// GPIOA_CRH |= (GPIO_MODE_OUTPUT_2_MHZ << ((5 - 8) * 4));
 	/* Using API functions: */
-	gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
+	gpio_set_mode(DHT_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, DHT_PIN);
 	gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO1);
 	gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO2);
 }
@@ -52,109 +71,148 @@ static void gpio_setup(void)
 static void tim_setup(void)
 {
 	nvic_enable_irq(NVIC_TIM3_IRQ);
-	nvic_set_priority(NVIC_TIM3_IRQ, 1);  // interupts will not work without it???
+	nvic_set_priority(NVIC_TIM3_IRQ, 1);  // interrupts will not work without it???
 
 	rcc_periph_clock_enable(RCC_TIM3);
 	rcc_periph_reset_pulse(RST_TIM3);
 
 	timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
-	timer_set_prescaler(TIM3, 1152);  // set timer tickrate to 500khz
+	timer_set_prescaler(TIM3, (rcc_apb1_frequency*2) / 1000000 - 1);  // set timer tickrate to 1mhz
-	//timer_set_oc_value(TIM3, TIM_OC1, 0x1000);
 	timer_set_period(TIM3, 0xffff);
-	timer_one_shot_mode(TIM3);
+	//timer_one_shot_mode(TIM3);
 
 	timer_ic_set_input(TIM3, TIM_IC3, TIM_IC_IN_TI3);
+	//timer_ic_set_filter(TIM3, TIM_IC3, 0b1111); // does not do anything ????
 	//timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING); // TIM_IC_RISING
 	//timer_ic_enable(TIM3, TIM_IC3);
 
-	timer_enable_counter(TIM3);
 	timer_enable_irq(TIM3, TIM_DIER_UIE);
-	timer_enable_irq(TIM3, TIM_DIER_CC1IE);  // end start condition
+	timer_enable_irq(TIM3, TIM_DIER_CC1IE);  // triggered when DHT11_END_START
-	timer_enable_irq(TIM3, TIM_DIER_CC3IE);
+	timer_enable_irq(TIM3, TIM_DIER_CC3IE);  // triggered when DHT drives DATA pin
 
-	// start condition
-	gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO0);
-	gpio_clear(GPIOB, GPIO0);
 }
 
-enum DHT11_STATE {
-	DHT11_START,
-	DHT11_RESPONSE,
-	DHT11_BIT0,
-	DHT11_BIT1,
-	DHT11_END
-};
-
-int dht11_state = DHT11_START;
-
 void tim3_isr(void)
 {
+	// Timer overflow that should only happen if DHT11 does not answer
+	if (timer_get_flag(TIM3, TIM_SR_UIF)) {
 
-	if (timer_get_flag(TIM3, TIM_SR_UIF))  // timer reached end
-	{
 		timer_clear_flag(TIM3, TIM_SR_UIF);
-		//gpio_toggle(GPIOB, GPIO1);
+		//gpio_toggle(GPIOB, GPIO2);
-		gpio_toggle(GPIOB, GPIO2);
+		if (g_dht11_state == DHT11_RESPONSE) {
+			puts("no response");
+		} else if (g_dht11_state == DHT11_DATA) {
+			puts("got data");
+		} else {
+			puts("overflow");
+		}
+		g_dht11_state = DHT11_STOP;
+		timer_disable_counter(TIM3);
 
 		//timer_set_counter(TIM3, 0);
 		//timer_clear_flag(TIM3, TIM_SR_UIF);
 		//timer_set_oc_value(TIM3, TIM_OC1, 1000);
-	} else if (timer_get_flag(TIM3, TIM_SR_CC1IF))
+	}
-	{
+
-		timer_clear_flag(TIM3, TIM_SR_CC3IF);
+	// handle DHT11_END_START
-		if (dht11_state == DHT11_START){
+	else if (timer_get_flag(TIM3, TIM_SR_CC1IF)) {
-			gpio_set(GPIOB, GPIO0);
+		timer_clear_flag(TIM3, TIM_SR_CC1IF);
-			gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
+		//gpio_toggle(GPIOB, GPIO2);
+		if (g_dht11_state == DHT11_BEGIN_START) {
+			g_dht11_state = DHT11_END_START;
+
+			// And make the GPIO input so that we can wait for response
+			gpio_set(DHT_PORT, DHT_PIN);
+			gpio_set_mode(DHT_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, DHT_PIN);
 
 			// setup timer to wait for start response from dht11
-			timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING); // TIM_IC_RISING
+			//timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING);// TIM_IC_RISING
+			timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_RISING);// TIM_IC_RISING
 			timer_ic_enable(TIM3, TIM_IC3);
-
-			dht11_state = DHT11_START;
-		}
-
-	} else if (timer_get_flag(TIM3, TIM_SR_CC3IF))  // PB0 changed value
-	{
 			timer_clear_flag(TIM3, TIM_SR_CC3IF);
+			//puts("waiting for response");
+		}
+		gpio_toggle(GPIOB, GPIO2);
+	}
 
-
+	else if (timer_get_flag(TIM3, TIM_SR_CC3IF))  // PB0 changed value
-
-		if (timer_get_flag(TIM3, TIM_SR_CC3OF))
 	{
-			timer_clear_flag(TIM3, TIM_SR_CC3OF);
+		if (g_dht11_state == DHT11_END_START) {
+			g_dht11_state = DHT11_RESPONSE;
+			gpio_toggle(GPIOB, GPIO2);
+			//timer_ic_disable(TIM3, TIM_IC3);
+			//timer_clear_flag(TIM3, TIM_SR_CC3IF);
+			//timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING);// TIM_IC_RISING
+			g_dht_vals[g_dht_i++] = TIM_CCR3(TIM3);				 // store captured high time value
+			//timer_ic_enable(TIM3, TIM_IC3);
+			gpio_toggle(GPIOB, GPIO2);
+		} else {
+			gpio_toggle(GPIOB, GPIO2);
+			g_dht11_state = DHT11_DATA;
+			g_dht_vals[g_dht_i] = TIM_CCR3(TIM3) - g_dht_vals[g_dht_i-1]; // store length from last sample
+			g_dht_i++;
+			gpio_toggle(GPIOB, GPIO2);
 		}
+
+//		if (timer_get_flag(TIM3, TIM_SR_CC3OF))
+//		{
+//			timer_clear_flag(TIM3, TIM_SR_CC3OF);
+//			puts("we are too slow to read and clear timer input capture flags");
+//		}
 	}
 
 }
 
+static void dht_start(void)
+{
+	timer_disable_counter(TIM3);
+	g_dht11_state = DHT11_BEGIN_START;
+	g_dht_i = 0;
+
+	// Setup DHT11_END_START trigger on output compare 1
+	timer_set_counter(TIM3, 0);
+	timer_set_oc_value(TIM3, TIM_OC1, 1000*20);  // 20ms
+	timer_clear_flag(TIM3, TIM_SR_CC1IF);
+
+	// Do DHT11_BEGIN_START aka drive DATA Low
+	gpio_set_mode(DHT_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, DHT_PIN);
+	gpio_clear(DHT_PORT, DHT_PIN);
+
+	// And start counting
+	timer_enable_counter(TIM3);
+
+	//gpio_toggle(GPIOB, GPIO2);
+
+}
+
 static void dht_start_signal(void)
 {
-	gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO0);
+	gpio_set_mode(DHT_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, DHT_PIN);
-	gpio_clear(GPIOB, GPIO0);
+	gpio_clear(DHT_PORT, DHT_PIN);
-	delay(205000);
+	delay(100000);
 	//delay(30000);
-	gpio_set(GPIOB, GPIO0);
+	gpio_set(DHT_PORT, DHT_PIN);
 	delay(100);
-	gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
+	gpio_set_mode(DHT_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, DHT_PIN);
 }
 
 int main(void)
 {
 	int i = 0;
-	SEGGER_RTT_printf(0, "Start\n");
+	puts("Start");
 	rcc_clock_setup_pll(&rcc_hse_configs[RCC_CLOCK_HSE8_72MHZ]);
 	gpio_setup();
-	//tim_setup();
+	tim_setup();
 
 	/* Blink the LED (PA5) on the board. */
 	while (1) {
 		/* Using API function gpio_toggle(): */
 		gpio_toggle(GPIOB, GPIO1);	/* LED on/off */
-		delay(4000000);
+		delay(10000000);
-		//dht_start_signal();
+		dht_start();
 
 		i++;
-		SEGGER_RTT_printf(0, "hello: %d\n", i);
+		SEGGER_RTT_printf(0, "Poll: %d\n", i);
 	}
 
 	return 0;

openocd.cfg

@@ -22,6 +22,7 @@ source [find target/stm32f1x.cfg]
 
 reset_config srst_only
 
+# Search for RTT string from start of RAM
 rtt setup 0x20000000 8192 "SEGGER RTT"
 rtt server start 9090 0