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Alex B.
2024-07-08 23:08:50 -04:00
parent 0f1144416d
commit 66eb49e65d
2 changed files with 12 additions and 3 deletions
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13
ESP32-IDF_BMP280/main/main.c
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@@ -138,7 +138,6 @@ static esp_err_t i2c_driver_initialize(void)
void app_main(void) void app_main(void)
{ {
// CONNECT TO BMP280 // CONNECT TO BMP280
//
ESP_ERROR_CHECK(i2c_driver_initialize()); ESP_ERROR_CHECK(i2c_driver_initialize());
i2c_driver_install(I2C_NUM_0, I2C_MODE_MASTER, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0); i2c_driver_install(I2C_NUM_0, I2C_MODE_MASTER, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0);
uint8_t address = 0x76; uint8_t address = 0x76;
@@ -154,22 +153,32 @@ void app_main(void)
else else
ESP_LOGI(TAG, "error %X", cmd_ret); ESP_LOGI(TAG, "error %X", cmd_ret);
// REQUEST DEVICE ID
// The sequence of commands corresponds to the BME-280 I2C protocol
int len = 1; // 1 byte int len = 1; // 1 byte
uint8_t *data = malloc(len); uint8_t *data = malloc(len);
//uint8_t address = 0x76; //uint8_t address = 0x76;
uint8_t register_address = 0xD0; uint8_t register_address = 0xD0; // Register that stores device ID
ESP_ERROR_CHECK(i2c_driver_initialize()); ESP_ERROR_CHECK(i2c_driver_initialize());
i2c_driver_install(I2C_NUM_0, I2C_MODE_MASTER, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0); i2c_driver_install(I2C_NUM_0, I2C_MODE_MASTER, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0);
command = i2c_cmd_link_create(); command = i2c_cmd_link_create();
// Step 1. START
i2c_master_start(command); i2c_master_start(command);
// Step 2. Send device address, WRITE bit, and wait for acknowledgment
i2c_master_write_byte(command, address << 1 | I2C_MASTER_WRITE, 0x1); i2c_master_write_byte(command, address << 1 | I2C_MASTER_WRITE, 0x1);
// Step 3. Specify (write) register address, and wait for acknowledgment
i2c_master_write_byte(command, register_address, 0x1); i2c_master_write_byte(command, register_address, 0x1);
// Step 4. START
i2c_master_start(command); i2c_master_start(command);
// Step 5. Send device address, READ bit, and wait for acknowledgment
i2c_master_write_byte(command, address << 1 | I2C_MASTER_READ, 0x1); i2c_master_write_byte(command, address << 1 | I2C_MASTER_READ, 0x1);
if (len > 1) if (len > 1)
i2c_master_read(command, data, len-1, 0x0); i2c_master_read(command, data, len-1, 0x0);
// Step 6. Read one byte of data from register
i2c_master_read_byte(command, data+len-1, 0x1); i2c_master_read_byte(command, data+len-1, 0x1);
// Step 8. STOP
i2c_master_stop(command); i2c_master_stop(command);
// Step 7. Read one byte of data from register
cmd_ret = i2c_master_cmd_begin(I2C_NUM_0, command, 1000 / portTICK_PERIOD_MS); cmd_ret = i2c_master_cmd_begin(I2C_NUM_0, command, 1000 / portTICK_PERIOD_MS);
i2c_cmd_link_delete(command); i2c_cmd_link_delete(command);
if (cmd_ret == ESP_OK) { if (cmd_ret == ESP_OK) {

2
README.md
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@@ -97,7 +97,7 @@ BME-/BMP-280 can communicate via I<sup>2</sup>C. The two diagrams below summariz
<img alt="BME-/BMP-280 I2C Read & Write" src="https://github.com/alexandrebobkov/ESP-Nodes/blob/main/assets/bme280_i2c_read-write.png" width="100%"/> <img alt="BME-/BMP-280 I2C Read & Write" src="https://github.com/alexandrebobkov/ESP-Nodes/blob/main/assets/bme280_i2c_read-write.png" width="100%"/>
--- ---
REFERENCES ## REFERENCES
[^2]: https://www.bosch-sensortec.com/products/environmental-sensors/humidity-sensors-bme280/ [^2]: https://www.bosch-sensortec.com/products/environmental-sensors/humidity-sensors-bme280/
[^3]: https://www.bosch-sensortec.com/products/environmental-sensors/pressure-sensors/bmp280/ [^3]: https://www.bosch-sensortec.com/products/environmental-sensors/pressure-sensors/bmp280/