Page 11 of 16
Page 274
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/i2c_master.h"
void app_main(void)
{
i2c_master_bus_config_t i2cBus = {
.i2c_port = I2C_NUM_0,
.scl_io_num = 15,
.sda_io_num = 16,
.clk_source = I2C_CLK_SRC_DEFAULT,
.glitch_ignore_cnt = 7,
.flags.enable_internal_pullup = true};
i2c_master_bus_handle_t bus_handle;
i2c_new_master_bus(&i2cBus, &bus_handle);
i2c_device_config_t i2cdev = {
.dev_addr_length = I2C_ADDR_BIT_LEN_7,
.device_address = 0x40,
.scl_speed_hz = 100000,
.scl_wait_us = 10};
i2c_master_dev_handle_t dev_handle;
i2c_master_bus_add_device(bus_handle, &i2cdev, &dev_handle);
uint8_t buf[10] = {0xE7};
i2c_master_transmit(dev_handle, buf, 1, 1000);
i2c_master_receive(dev_handle, buf, 1, 100);
printf("User Register = %X \r\n", buf[0]);
}
Page 278
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/i2c_master.h"
void app_main(void)
{
i2c_master_bus_config_t i2cBus = {
.i2c_port = I2C_NUM_0,
.scl_io_num = 15,
.sda_io_num = 16,
.clk_source = I2C_CLK_SRC_DEFAULT,
.glitch_ignore_cnt = 7,
.flags.enable_internal_pullup = true};
i2c_master_bus_handle_t bus_handle;
i2c_new_master_bus(&i2cBus, &bus_handle);
i2c_device_config_t i2cdev = {
.dev_addr_length = I2C_ADDR_BIT_LEN_7,
.device_address = 0x40,
.scl_speed_hz = 100000,
.scl_wait_us = 10};
i2c_master_dev_handle_t dev_handle;
i2c_master_bus_add_device(bus_handle, &i2cdev, &dev_handle);
uint8_t buf[10] = {0xF3};
i2c_master_transmit(dev_handle, buf, 1, 100);
esp_err_t err;
do
{
err = i2c_master_receive(dev_handle, buf, 3, 100);
if (err != ESP_OK)
{
i2c_master_bus_rm_device(dev_handle);
i2c_del_master_bus(bus_handle);
i2c_new_master_bus(&i2cBus, &bus_handle);
i2c_master_bus_add_device(bus_handle, &i2cdev, &dev_handle);
};
} while (err != ESP_OK);
uint8_t msb = buf[0];
uint8_t lsb = buf[1];
uint8_t check = buf[2];
printf("msb %d \n lsb %d \n checksum %d \n", msb, lsb, check);
fflush(stdout);
}
Page 278 complete program from fragment
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/i2c_master.h"
void app_main(void)
{
i2c_master_bus_config_t i2cBus = {
.i2c_port = I2C_NUM_0,
.scl_io_num = 15,
.sda_io_num = 16,
.clk_source = I2C_CLK_SRC_DEFAULT,
.glitch_ignore_cnt = 7,
.flags.enable_internal_pullup = true};
i2c_master_bus_handle_t bus_handle;
i2c_new_master_bus(&i2cBus, &bus_handle);
i2c_device_config_t i2cdev = {
.dev_addr_length = I2C_ADDR_BIT_LEN_7,
.device_address = 0x40,
.scl_speed_hz = 100000,
.scl_wait_us = 10};
i2c_master_dev_handle_t dev_handle;
i2c_master_bus_add_device(bus_handle, &i2cdev, &dev_handle);
uint8_t buf[10] = {0xF3};
i2c_master_transmit(dev_handle, buf, 1, 100);
esp_err_t err;
do
{
err = i2c_master_receive(dev_handle, buf, 3, 100);
vTaskDelay(10 / portTICK_PERIOD_MS);
} while (err != ESP_OK);
uint8_t msb = buf[0];
uint8_t lsb = buf[1];
uint8_t check = buf[2];
printf("msb %d \n lsb %d \n checksum %d \n", msb, lsb, check);
fflush(stdout);
}
Page 279 Complete program from fragment
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/i2c_master.h"
void app_main(void)
{
i2c_master_bus_config_t i2cBus = {
.i2c_port = I2C_NUM_0,
.scl_io_num = 15,
.sda_io_num = 16,
.clk_source = I2C_CLK_SRC_DEFAULT,
.glitch_ignore_cnt = 7,
.flags.enable_internal_pullup = true};
i2c_master_bus_handle_t bus_handle;
i2c_new_master_bus(&i2cBus, &bus_handle);
i2c_device_config_t i2cdev = {
.dev_addr_length = I2C_ADDR_BIT_LEN_7,
.device_address = 0x40,
.scl_speed_hz = 100000,
.scl_wait_us = 10};
i2c_master_dev_handle_t dev_handle;
i2c_master_bus_add_device(bus_handle, &i2cdev, &dev_handle);
uint8_t buf[10] = {0xF3};
i2c_master_transmit(dev_handle, buf, 1, 100);
vTaskDelay(50 / portTICK_PERIOD_MS);
i2c_master_receive(dev_handle, buf, 3, 100);
uint8_t msb = buf[0];
uint8_t lsb = buf[1];
uint8_t check = buf[2];
printf("msb %d \n lsb %d \n checksum %d \n", msb, lsb, check);
fflush(stdout);
}
Page 282
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/i2c_master.h"
uint8_t crcCheck(uint8_t msb, uint8_t lsb, uint8_t check)
{
uint32_t data32 = ((uint32_t)msb << 16) | ((uint32_t)lsb << 8) |
(uint32_t)check;
uint32_t divisor = 0x988000;
for (int i = 0; i < 16; i++)
{
if (data32 & (uint32_t)1 << (23 - i))
data32 ^= divisor;
divisor >>= 1;
};
return (uint8_t)data32;
}
void app_main(void)
{
i2c_master_bus_config_t i2cBus = {
.i2c_port = I2C_NUM_0,
.scl_io_num = 15,
.sda_io_num = 16,
.clk_source = I2C_CLK_SRC_DEFAULT,
.glitch_ignore_cnt = 7,
.flags.enable_internal_pullup = true};
i2c_master_bus_handle_t bus_handle;
i2c_new_master_bus(&i2cBus, &bus_handle);
i2c_device_config_t i2cdev = {
.dev_addr_length = I2C_ADDR_BIT_LEN_7,
.device_address = 0x40,
.scl_speed_hz = 100000,
.scl_wait_us = 10};
i2c_master_dev_handle_t dev_handle;
i2c_master_bus_add_device(bus_handle, &i2cdev, &dev_handle);
uint8_t buf[10] = {0xF3};
i2c_master_transmit(dev_handle, buf, 1, 100);
vTaskDelay(50 / portTICK_PERIOD_MS);
i2c_master_receive(dev_handle, buf, 3, 100);
uint8_t msb = buf[0];
uint8_t lsb = buf[1];
uint8_t check = buf[2];
unsigned int data16 = ((unsigned int)msb << 8) |
(unsigned int)(lsb & 0xFC);
float temp = (float)(-46.85 + (175.72 * data16 / (float)65536));
printf("Temperature %f C \n\r", temp);
printf("crc = %d\n\r", crcCheck(msb, lsb, check));
buf[0] = 0xF5;
i2c_master_transmit(dev_handle, buf, 1, 100);
vTaskDelay(50 / portTICK_PERIOD_MS);
i2c_master_receive(dev_handle, buf, 3, 100);
msb = buf[0];
lsb = buf[1];
check = buf[2];
data16 = ((unsigned int)msb << 8) | (unsigned int)(lsb & 0xFC);
float hum = -6 + (125.0 * (float)data16) / 65536;
printf("Humidity %f %% \n\r", hum);
printf("crc = %d\n\r", crcCheck(msb, lsb, check));
}
