fix i2c reset bus function

Inc/i2c.h

@@ -39,7 +39,10 @@ typedef enum {
     I2C_RESULT_NACK,            /* No acknowledge received */
     I2C_RESULT_BUS_BUSY,        /* Bus is busy */
     I2C_RESULT_ERROR,           /* General error */
-    I2C_RESULT_INVALID_PARAM    /* Invalid parameter */
+    I2C_RESULT_INVALID_PARAM,   /* Invalid parameter */
+    I2C_RECOVERY_OK,
+    I2C_RECOVERY_SDA_STUCK_LOW,
+    I2C_RECOVERY_SCL_STUCK_LOW
 } i2c_result_t;
 
 /* I2C state machine enumeration */
@@ -69,24 +72,21 @@ typedef enum {
 
 
 /* Function declarations */
-
-// TODO I2C Result
 /*!
     \brief      configure the I2C interface
     \param[in]  none
     \param[out] none
     \retval     i2c_result_t
 */
-void i2c_config(void);
+i2c_result_t i2c_config(void);
 
-// TODO I2C Result
 /*!
     \brief      reset I2C bus with proper recovery
     \param[in]  none
     \param[out] none
     \retval     i2c_result_t
 */
-void i2c_bus_reset(void);
+i2c_result_t i2c_bus_reset(void);
 
 /*!
     \brief      scan I2C bus for devices

Src/i2c.c

@@ -31,7 +31,7 @@ void i2c_gpio_config(void) {
     \param[out] none
     \retval     none
 */
-void i2c_config(void) {
+i2c_result_t i2c_config(void) {
     /* configure I2C GPIO */
     i2c_gpio_config();
     /* enable I2C clock */
@@ -44,6 +44,26 @@ void i2c_config(void) {
     i2c_enable(I2C0);
     /* enable acknowledge */
     i2c_ack_config(I2C0, I2C_ACK_ENABLE);
+
+    return I2C_RESULT_SUCCESS;
+}
+
+static bool i2c_wait_scl_high(uint16_t max_wait_time) {
+    while (max_wait_time--) {
+        if (gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN)) {
+            return true;
+        }
+        delay_10us(1);
+    }
+    return false;
+}
+
+/* generate one manual SCL pulse; return true if SCL observed high (no stuck/overstretch) */
+static bool i2c_generate_scl_pulse(void) {
+    GPIO_BC(I2C_SCL_PORT) = I2C_SCL_PIN;   /* drive SCL low */
+    delay_10us(1);
+    GPIO_BOP(I2C_SCL_PORT) = I2C_SCL_PIN;  /* release SCL (open-drain -> high via pull-up) */
+    return i2c_wait_scl_high(200);         /* wait up to ~2ms for clock stretching release */
 }
 
 /*!
@@ -52,31 +72,87 @@ void i2c_config(void) {
     \param[out] none
     \retval     none
 */
-void i2c_bus_reset(void) {
+i2c_result_t i2c_bus_reset(void) {
+    /* 1. Disable & deinit peripheral so pins can be fully controlled */
+    i2c_disable(I2C0);
     i2c_deinit(I2C0);
-    /* configure SDA/SCL for GPIO */
+
-    GPIO_BC(I2C_SCL_PORT) |= I2C_SCL_PIN;
+#ifdef DEBUG_VERBOSE
-    GPIO_BC(I2C_SDA_PORT) |= I2C_SDA_PIN;
+    printf("I2C bus reset\r\n");
-    gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
+#endif
-    gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
+
-    __NOP();
+    /* 2. Configure SCL/SDA as GPIO open-drain outputs with pull-up and release them */
-    __NOP();
+    gpio_mode_set(I2C_SCL_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, I2C_SCL_PIN);
-    __NOP();
+    gpio_mode_set(I2C_SDA_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, I2C_SDA_PIN);
-    __NOP();
-    __NOP();
-    GPIO_BOP(I2C_SCL_PORT) |= I2C_SCL_PIN;
-    __NOP();
-    __NOP();
-    __NOP();
-    __NOP();
-    __NOP();
-    GPIO_BOP(I2C_SDA_PORT) |= I2C_SDA_PIN;
-    /* connect I2C_SCL_PIN to I2C_SCL */
-    /* connect I2C_SDA_PIN to I2C_SDA */
     gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
     gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
-    /* configure the I2CX interface */
+    gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN); /* release SCL */
+    gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN); /* release SDA */
+
+#ifdef DEBUG_VERBOSE
+    printf("I2C bus reset: SCL = %d, SDA = %d\r\n", gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN), gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN));
+#endif
+
+    /* 3. Double sample to confirm bus state */
+    delay_10us(1);
+    bool scl_value1 = gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN);
+    bool sda_value1 = gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN);
+    delay_10us(1);
+    bool scl_value2 = gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN);
+    bool sda_value2 = gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN);
+
+    /* 4. If SCL low -> stuck (cannot proceed) */
+    if (!scl_value2) {
+#ifdef DEBUG_VERBOSE
+        printf("I2C bus reset: SCL stuck low\r\n");
+#endif
+        return I2C_RECOVERY_SCL_STUCK_LOW;
+    }
+
+    /* 5. Fast path: bus idle */
+    if (scl_value1 && sda_value1 && scl_value2 && sda_value2) {
+        i2c_config();
+#ifdef DEBUG_VERBOSE
+        printf("I2C bus reset: bus idle\r\n");
+#endif
+        return I2C_RECOVERY_OK;
+    }
+
+    /* 6. SDA low: attempt to free by generating up to I2C_RECOVERY_CLOCKS pulses */
+    if (scl_value2 && !sda_value2) {
+        bool sda_released = false;
+#ifdef DEBUG_VERBOSE
+        printf("I2C bus reset: SCL will try to free SDA\r\n");
+#endif
+        for (uint8_t i = 0; i < I2C_RECOVERY_CLOCKS && !sda_released; i++) {
+            if (!i2c_generate_scl_pulse()) {
+                return I2C_RECOVERY_SCL_STUCK_LOW; /* SCL failed to go high */
+            }
+            if (gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN)) {
+                sda_released = true;
+            }
+        }
+        if (!sda_released) {
+            return I2C_RECOVERY_SDA_STUCK_LOW;
+        }
+        /* 7. Generate a STOP condition to leave bus in idle state */
+#ifdef DEBUG_VERBOSE
+        printf("I2C bus reset: generating STOP condition\r\n");
+#endif
+        gpio_bit_reset(I2C_SDA_PORT, I2C_SDA_PIN); /* SDA low */
+        delay_10us(1);
+        gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN);   /* ensure SCL high */
+        delay_10us(1);
+        gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN);   /* SDA rising while SCL high -> STOP */
+        delay_10us(1);
+    }
+
+#ifdef DEBUG_VERBOSE
+        printf("I2C bus reset: bus recovered\r\n");
+#endif
+    /* 8. Reconfigure & enable peripheral */
     i2c_config();
+    return I2C_RECOVERY_OK;
 }
 
 /**

Src/main.c

@@ -60,7 +60,7 @@ int main(void)
     led_init();
 
 #ifdef DEBUG_VERBOSE
-    char hello_world[] = {"Hello World!"};
+    char hello_world[] = {"Hello World!\r\n"};
 
     for (uint8_t i = 0; i < sizeof(hello_world); i++)
     {
@@ -69,29 +69,23 @@ int main(void)
     }
     
     while (usart_flag_get(RS485_PHY, USART_FLAG_TC) == RESET) {}
-#endif
 
     
+#endif
 
+#ifdef DEBUG_VERBOSE
     i2c_config();
 
     i2c_scan();
 
-    // i2c_bus_reset();
+    i2c_bus_reset();
-
+    
-    // uint8_t sensor_data[2] = {0};
+    i2c_scan();
-
+#endif
-    // i2c_read_16bits(0x2B, 0x7E, sensor_data);
-
-    // printf("Sensor Data: 0x%02X 0x%02X\r\n", sensor_data[0], sensor_data[1]);
-
-    // i2c_bus_reset();
 
     ldc1612_iic_get_sensor_infomation();
 
-#ifdef DEBUG_VERBOSE
+
-    i2c_scan();
-#endif
 
     while(1){
         command_process();