From eaad822677079cfc7bd1248531418a5a9b94708b Mon Sep 17 00:00:00 2001
From: Radzhab Bisultanov <bisultanov@sfedu.ru>
Date: Tue, 3 Mar 2026 17:51:24 +0300
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---
 Source/BSP/Inc/lidar.h |  6 +++-
 Source/BSP/Src/lidar.c | 78 ++++++++++++++++++++++--------------------
 Source/main.c          |  2 +-
 3 files changed, 47 insertions(+), 39 deletions(-)

diff --git a/Source/BSP/Inc/lidar.h b/Source/BSP/Inc/lidar.h
index 32d0848..07c0fc0 100644
--- a/Source/BSP/Inc/lidar.h
+++ b/Source/BSP/Inc/lidar.h
@@ -6,6 +6,7 @@
 #include "stm32g431xx.h"
 
 #define USART3_START_BYTE	0x59
+#define USART3_BUF_SIZE		64
 #define USART3_FRAME_SIZE	9
 #define LIDAR_MIN_DIST		0.01f
 #define LIDAR_MAX_DIST		40.0f
@@ -26,7 +27,7 @@ typedef struct
 
 typedef struct
 {
-	uint16_t distance;		// meters
+	uint16_t distance;		// cm
 	uint16_t strength;
 	uint16_t temperature;
 } lidar_data;
@@ -37,6 +38,9 @@ void TIM7_DAC_IRQHandler();
 void USART3_IRQHandler();
 void lidar_update(lidar_data* lidar);
 
+uint8_t usart_available();
+uint8_t usart_read();
+
 void lidar_i2c2_init();
 static void i2c2_wait_txis();
 static void i2c2_wait_stop();
diff --git a/Source/BSP/Src/lidar.c b/Source/BSP/Src/lidar.c
index 9cdcb41..4ff2ea1 100644
--- a/Source/BSP/Src/lidar.c
+++ b/Source/BSP/Src/lidar.c
@@ -1,11 +1,8 @@
 #include "lidar.h"
 
-volatile uint8_t usart3_index = 0;
-volatile uint8_t usart3_checksum = 0;
-volatile uint8_t usart3_frame_ready = 0;
-volatile uint8_t lidar_update_flag = 0;
-static lidar_data_buf buffer;
-static uint8_t* buff_data = (uint8_t*)&buffer;
+volatile uint8_t usart3_rx_buf[USART3_BUF_SIZE];
+static uint8_t usart3_rx_head = 0;
+static uint8_t usart3_rx_tail = 0;
 
 void lidar_init()
 {
@@ -78,7 +75,7 @@ void TIM7_DAC_IRQHandler()
 	if (TIM7->SR & TIM_SR_UIF)
 	{
 		TIM7->SR &= ~TIM_SR_UIF;
-		lidar_update_flag = 1;
+		//lidar_update_flag = 1;
 	}
 }
 	
@@ -86,42 +83,49 @@ void USART3_IRQHandler()
 {
 	if (USART3->ISR & USART_ISR_RXNE)
 	{
-		uint8_t b = USART3->RDR;
-		
-		if (usart3_index < 2)
-		{
-			if (b == USART3_START_BYTE)
-				buff_data[usart3_index++] = b;
-		}
-		else if (usart3_index < USART3_FRAME_SIZE)
-			buff_data[usart3_index++] = b;
-		
-		if (usart3_index == USART3_FRAME_SIZE)
-		{
-			usart3_index = 0;
-			usart3_frame_ready = 1;
-		}
+		usart3_rx_buf[usart3_rx_head] = USART3->RDR;
+		usart3_rx_head = (usart3_rx_head + 1) % USART3_BUF_SIZE;
 	}
 }
 
+uint8_t usart_available()
+{
+	return usart3_rx_head != usart3_rx_tail;
+}
+
+uint8_t usart_read()
+{
+	uint8_t data = usart3_rx_buf[usart3_rx_tail];
+	usart3_rx_tail = (usart3_rx_tail + 1) % USART3_BUF_SIZE;
+	return data;
+}
+
 void lidar_update(lidar_data* lidar)
 {
-	if (!lidar_update_flag)
-		return;
+	static uint8_t frame[USART3_FRAME_SIZE];
+	static uint8_t index = 0;
 	
-	if (!usart3_frame_ready)
-		return;
-	
-	usart3_frame_ready = 0;
-	
-	for (uint8_t i = 0; i < USART3_FRAME_SIZE; ++i) usart3_checksum += buff_data[i];
-	
-	if (buffer.checksum != usart3_checksum)
-	  return;
-	
-	lidar->distance		= 	buffer.distance_l 	| (buffer.distance_h << 8);
-	lidar->strength		= 	buffer.strength_l 	| (buffer.strength_h << 8);
-	lidar->temperature	= 	buffer.temp_l 		| (buffer.temp_h << 8);
+	while(usart_available())
+	{
+		uint8_t c = usart_read();
+		
+		frame[index++] = c;
+		
+		if (index == USART3_FRAME_SIZE)
+		{
+			uint8_t checksum = 0;
+			for (uint8_t i = 0; i < USART3_FRAME_SIZE - 1; ++i) checksum += frame[i];
+			
+			if (checksum == frame[USART3_FRAME_SIZE - 1])
+			{
+				lidar->distance 	= frame[2] | (frame[3] << 8);
+                lidar->strength 	= frame[4] | (frame[5] << 8);
+                lidar->temperature 	= frame[6] | (frame[7] << 8);
+			}
+			
+			index = 0;
+		}
+	}
 }
 
 void lidar_i2c2_init()
diff --git a/Source/main.c b/Source/main.c
index edbf6be..e2637f6 100644
--- a/Source/main.c
+++ b/Source/main.c
@@ -39,7 +39,7 @@ int main(void)
 	motors_init();*/
 	
 	lidar_init();
-	lidar_tim7_init();
+	// lidar_tim7_init();
 	
 	while (1)
 	{