Outline ![]()
Files ![]()
loading...
SourceVu![]()
ESP-IDF Framework and Examples![]()
onewire sample![]()
managed_components/espressif__ds18b20/src/ds18b20.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
/*
* SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_check.h"
#include "onewire_bus.h"
#include "onewire_cmd.h"
#include "onewire_crc.h"
#include "ds18b20.h"
static const char *TAG = "ds18b20";
#define DS18B20_CMD_CONVERT_TEMP 0x44
#define DS18B20_CMD_WRITE_SCRATCHPAD 0x4E
#define DS18B20_CMD_READ_SCRATCHPAD 0xBE
/**
* @brief Structure of DS18B20's scratchpad
*/
typedef struct {
uint8_t temp_lsb; /*!< lsb of temperature */
uint8_t temp_msb; /*!< msb of temperature */
uint8_t th_user1; /*!< th register or user byte 1 */
uint8_t tl_user2; /*!< tl register or user byte 2 */
uint8_t configuration; /*!< resolution configuration register */
uint8_t _reserved1;
uint8_t _reserved2;
uint8_t _reserved3;
uint8_t crc_value; /*!< crc value of scratchpad data */
} __attribute__((packed)) ds18b20_scratchpad_t;
typedef struct ds18b20_device_t {
onewire_bus_handle_t bus;
bool single_mode;
onewire_device_address_t addr;
uint8_t th_user1;
uint8_t tl_user2;
ds18b20_resolution_t resolution;
} ds18b20_device_t;
esp_err_t ds18b20_new_device(onewire_device_t *device, const ds18b20_config_t *config, ds18b20_device_handle_t *ret_ds18b20)
{
ds18b20_device_t *ds18b20 = NULL;
ESP_RETURN_ON_FALSE(device && config && ret_ds18b20, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
// check ROM ID, the family code of DS18B20 is 0x28
if ((device->address & 0xFF) != 0x28) {
ESP_LOGD(TAG, "%016llX is not a DS18B20 device", device->address);
return ESP_ERR_NOT_SUPPORTED;
}
ds18b20 = calloc(1, sizeof(ds18b20_device_t));
ESP_RETURN_ON_FALSE(ds18b20, ESP_ERR_NO_MEM, TAG, "no mem for ds18b20");
ds18b20->bus = device->bus;
ds18b20->addr = device->address;
ds18b20->resolution = DS18B20_RESOLUTION_12B; // DS18B20 default resolution is 12 bits
*ret_ds18b20 = ds18b20;
return ESP_OK;
}
esp_err_t ds18b20_new_single_device(onewire_bus_handle_t bus, const ds18b20_config_t *config, ds18b20_device_handle_t *ret_ds18b20)
{
ds18b20_device_t *ds18b20 = NULL;
ESP_RETURN_ON_FALSE(bus && config && ret_ds18b20, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
ds18b20 = calloc(1, sizeof(ds18b20_device_t));
ESP_RETURN_ON_FALSE(ds18b20, ESP_ERR_NO_MEM, TAG, "no mem for ds18b20");
ds18b20->bus = bus;
ds18b20->addr = 0;
ds18b20->single_mode = true;
ds18b20->resolution = DS18B20_RESOLUTION_12B; // DS18B20 default resolution is 12 bits
*ret_ds18b20 = ds18b20;
return ESP_OK;
}
esp_err_t ds18b20_del_device(ds18b20_device_handle_t ds18b20)
{
ESP_RETURN_ON_FALSE(ds18b20, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
free(ds18b20);
return ESP_OK;
}
static esp_err_t ds18b20_send_command(ds18b20_device_handle_t ds18b20, uint8_t cmd)
{
// No addres mode (singe device connectd to the bus) created using ds18b20_new_single_device
if (ds18b20->single_mode) {
uint8_t tx_buffer[2] = {ONEWIRE_CMD_SKIP_ROM, cmd};
return onewire_bus_write_bytes(ds18b20->bus, tx_buffer, sizeof(tx_buffer));
}
// send command
uint8_t tx_buffer[10] = {0};
tx_buffer[0] = ONEWIRE_CMD_MATCH_ROM;
memcpy(&tx_buffer[1], &ds18b20->addr, sizeof(ds18b20->addr));
tx_buffer[sizeof(ds18b20->addr) + 1] = cmd;
return onewire_bus_write_bytes(ds18b20->bus, tx_buffer, sizeof(tx_buffer));
}
esp_err_t ds18b20_set_resolution(ds18b20_device_handle_t ds18b20, ds18b20_resolution_t resolution)
{
ESP_RETURN_ON_FALSE(ds18b20, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
// reset bus and check if the ds18b20 is present
ESP_RETURN_ON_ERROR(onewire_bus_reset(ds18b20->bus), TAG, "reset bus error");
// send command: DS18B20_CMD_WRITE_SCRATCHPAD
ESP_RETURN_ON_ERROR(ds18b20_send_command(ds18b20, DS18B20_CMD_WRITE_SCRATCHPAD), TAG, "send DS18B20_CMD_WRITE_SCRATCHPAD failed");
// write new resolution to scratchpad
const uint8_t resolution_data[] = {0x1F, 0x3F, 0x5F, 0x7F};
uint8_t tx_buffer[3] = {0};
tx_buffer[0] = ds18b20->th_user1;
tx_buffer[1] = ds18b20->tl_user2;
tx_buffer[2] = resolution_data[resolution];
ESP_RETURN_ON_ERROR(onewire_bus_write_bytes(ds18b20->bus, tx_buffer, sizeof(tx_buffer)), TAG, "send new resolution failed");
ds18b20->resolution = resolution;
return ESP_OK;
}
esp_err_t ds18b20_trigger_temperature_conversion(ds18b20_device_handle_t ds18b20)
{
ESP_RETURN_ON_FALSE(ds18b20, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
// reset bus and check if the ds18b20 is present
ESP_RETURN_ON_ERROR(onewire_bus_reset(ds18b20->bus), TAG, "reset bus error");
// send command: DS18B20_CMD_CONVERT_TEMP
ESP_RETURN_ON_ERROR(ds18b20_send_command(ds18b20, DS18B20_CMD_CONVERT_TEMP), TAG, "send DS18B20_CMD_CONVERT_TEMP failed");
// delay proper time for temperature conversion
const uint32_t delays_ms[] = {100, 200, 400, 800};
vTaskDelay(pdMS_TO_TICKS(delays_ms[ds18b20->resolution]));
return ESP_OK;
}
esp_err_t ds18b20_get_temperature(ds18b20_device_handle_t ds18b20, float *ret_temperature)
{
ESP_RETURN_ON_FALSE(ds18b20 && ret_temperature, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
// reset bus and check if the ds18b20 is present
ESP_RETURN_ON_ERROR(onewire_bus_reset(ds18b20->bus), TAG, "reset bus error");
// send command: DS18B20_CMD_READ_SCRATCHPAD
ESP_RETURN_ON_ERROR(ds18b20_send_command(ds18b20, DS18B20_CMD_READ_SCRATCHPAD), TAG, "send DS18B20_CMD_READ_SCRATCHPAD failed");
// read scratchpad data
ds18b20_scratchpad_t scratchpad;
ESP_RETURN_ON_ERROR(onewire_bus_read_bytes(ds18b20->bus, (uint8_t *)&scratchpad, sizeof(scratchpad)),
TAG, "error while reading scratchpad data");
// check crc
ESP_RETURN_ON_FALSE(onewire_crc8(0, (uint8_t *)&scratchpad, 8) == scratchpad.crc_value, ESP_ERR_INVALID_CRC, TAG, "scratchpad crc error");
const uint8_t lsb_mask[4] = {0x07, 0x03, 0x01, 0x00}; // mask bits not used in low resolution
uint8_t lsb_masked = scratchpad.temp_lsb & (~lsb_mask[scratchpad.configuration >> 5]);
// Combine the MSB and masked LSB into a signed 16-bit integer
int16_t temperature_raw = (((int16_t)scratchpad.temp_msb << 8) | lsb_masked);
// Convert the raw temperature to a float,
*ret_temperature = temperature_raw / 16.0f;
return ESP_OK;
}
Details ![]()
Show: from Types: Columns: ![]( "Show Project Names")
![]( "Show Locations")
![]( "Show Referring Symbols")
![]( "Show Scope")
This file uses the notable symbols shown below. Click anywhere in the file to view more details.