i2c: load and interprete temperature of seesaw

nucleo-wb55-i2c/Core/Src/main.c

@@ -59,7 +59,21 @@ static void MX_I2C1_Init(void);
 
 /* Private user code ---------------------------------------------------------*/
 /* USER CODE BEGIN 0 */
+HAL_StatusTypeDef i2c_write(uint16_t DevAddress, uint8_t *pData, uint16_t Size, uint32_t Timeout) {
+  //printf("I2C WRITE | address=0x%04x | size=0x%04x\n", DevAddress, Size);
+  return HAL_I2C_Master_Transmit(&hi2c1, DevAddress, pData, Size, Timeout);
+}
+
+HAL_StatusTypeDef i2c_read(uint16_t DevAddress, uint8_t *pData, uint16_t Size, uint32_t Timeout) {
+  //printf("I2C READ  | address=0x%04x | size=0x%04x\n", DevAddress, Size);
+  return HAL_I2C_Master_Receive(&hi2c1, DevAddress, pData, Size, Timeout);
+}
 
+float getTemp(uint8_t * buf) {
+  int32_t ret = ((uint32_t)buf[0] << 24) | ((uint32_t)buf[1] << 16) |
+                ((uint32_t)buf[2] << 8) | (uint32_t)buf[3];
+  return (1.0 / (1UL << 16)) * ret;
+}
 /* USER CODE END 0 */
 
 /**
@@ -105,10 +119,43 @@ int main(void)
   /* Infinite loop */
   /* USER CODE BEGIN WHILE */
   int index = 0;
+  HAL_StatusTypeDef i2c_status;
+  int ADAFRUIT_ADDR = 0x36 << 1;
+  const int BUF_LEN = 4;
+  uint8_t buf[BUF_LEN];
+  uint8_t prefix[2];
+  prefix[0] = 0x0;
+  prefix[1] = 0x4;
+
   while (1)
   {
-  	printf("test %d\n\r", index++);
+  	//printf("test %d\n\r", index++);
+    //HAL_Delay(100);
+
+    HAL_Delay(10);
+
+    i2c_status = i2c_write(ADAFRUIT_ADDR, prefix, 2, 1000);
+    if (i2c_status != HAL_OK) {
+      printf("ERROR: %d\n", (int)i2c_status);
+      Error_Handler();
+    }
+
     HAL_Delay(100);
+
+    i2c_status = i2c_read(ADAFRUIT_ADDR, buf, BUF_LEN, 1000);
+    if (i2c_status != HAL_OK) {
+      printf("ERROR: %d\n", (int)i2c_status);
+      Error_Handler();
+    }
+
+    //printf("Buffer: ");
+    for (int i = 0; i < BUF_LEN; i++) {
+      //printf("%d ", buf[i]);
+    }
+    //printf("\n");
+    
+    printf("Temperature: %2.2f degree celsius\n", getTemp(buf));
+
     /* USER CODE END WHILE */
 
     /* USER CODE BEGIN 3 */