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171 lines
3.3 KiB
171 lines
3.3 KiB
#include <stddef.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <inttypes.h> // for PRIu64
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "driver/gpio.h"
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#include "esp_system.h"
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#include "esp_log.h"
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#include "sdkconfig.h"
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#include "ds18b20.h"
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#include "owb.h"
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#define TAG "ds18b20"
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// Function commands
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#define DS18B20_FUNCTION_TEMP_CONVERT 0x44
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#define DS18B20_FUNCTION_SCRATCHPAD_WRITE 0x4E
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#define DS18B20_FUNCTION_SCRATCHPAD_READ 0xBE
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#define DS18B20_FUNCTION_SCRATCHPAD_COPY 0x48
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#define DS18B20_FUNCTION_EEPROM_RECALL 0xB8
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#define DS18B20_FUNCTION_POWER_SUPPLY_READ 0xB4
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struct _DS18B20_Info
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{
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bool init;
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bool use_crc;
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OneWireBus * bus;
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uint64_t rom_code;
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};
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static bool _is_init(const DS18B20_Info * ds18b20_info)
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{
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bool ok = false;
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if (ds18b20_info != NULL)
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{
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if (ds18b20_info->init)
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{
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// OK
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ok = true;
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}
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else
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{
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ESP_LOGE(TAG, "ds18b20_info is not initialised");
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}
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}
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else
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{
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ESP_LOGE(TAG, "ds18b20_info is NULL");
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}
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return ok;
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}
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DS18B20_Info * ds18b20_malloc(void)
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{
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DS18B20_Info * ds18b20_info = malloc(sizeof(*ds18b20_info));
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if (ds18b20_info != NULL)
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{
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memset(ds18b20_info, 0, sizeof(*ds18b20_info));
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ESP_LOGD(TAG, "malloc %p", ds18b20_info);
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}
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else
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{
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ESP_LOGE(TAG, "malloc failed");
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}
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return ds18b20_info;
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}
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void ds18b20_free(DS18B20_Info ** ds18b20_info)
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{
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if (ds18b20_info != NULL && (*ds18b20_info != NULL))
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{
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ESP_LOGD(TAG, "free %p", *ds18b20_info);
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free(*ds18b20_info);
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*ds18b20_info = NULL;
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}
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}
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void ds18b20_init(DS18B20_Info * ds18b20_info, OneWireBus * bus, uint64_t rom_code)
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{
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if (ds18b20_info != NULL)
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{
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ds18b20_info->bus = bus;
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ds18b20_info->rom_code = rom_code;
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ds18b20_info->use_crc = false;
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ds18b20_info->init = true;
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}
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else
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{
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ESP_LOGE(TAG, "ds18b20_info is NULL");
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}
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}
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void ds18b20_use_crc(DS18B20_Info * ds18b20_info, bool use_crc)
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{
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if (_is_init(ds18b20_info))
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{
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ds18b20_info->use_crc = use_crc;
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ESP_LOGD(TAG, "use_crc %d", ds18b20_info->use_crc);
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}
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}
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float ds18b20_get_temp(DS18B20_Info * ds18b20_info)
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{
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float temp = 0.0f;
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if (_is_init(ds18b20_info))
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{
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OneWireBus * bus = ds18b20_info->bus;
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if (owb_reset(bus))
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{
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//owb_write_byte(bus, OWB_ROM_SKIP);
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owb_write_byte(bus, OWB_ROM_MATCH);
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owb_write_rom_code(bus, ds18b20_info->rom_code);
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owb_write_byte(bus, DS18B20_FUNCTION_TEMP_CONVERT);
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vTaskDelay(750 / portTICK_PERIOD_MS);
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// reset
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owb_reset(bus);
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owb_write_byte(bus, OWB_ROM_SKIP);
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owb_write_byte(bus, DS18B20_FUNCTION_SCRATCHPAD_READ);
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uint8_t temp_LSB = 0;
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uint8_t temp_MSB = 0;
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if (ds18b20_info->use_crc)
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{
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// Without CRC:
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temp_LSB = owb_read_byte(bus);
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temp_MSB = owb_read_byte(bus);
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owb_reset(bus); // terminate early
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}
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else
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{
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// with CRC:
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uint8_t buffer[9];
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owb_read_bytes(bus, buffer, 9);
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temp_LSB = buffer[0];
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temp_MSB = buffer[1];
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uint8_t crc = 0;
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for (int i = 0; i < 9; ++i)
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{
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crc = owb_crc8(crc, buffer[i]);
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}
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ESP_LOGD(TAG, "crc 0x%02x", crc);
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if (crc != 0)
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{
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ESP_LOGE(TAG, "CRC failed");
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temp_LSB = temp_MSB = 0;
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}
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}
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ESP_LOGD(TAG, "temp_LSB 0x%02x, temp_MSB 0x%02x", temp_LSB, temp_MSB);
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temp = (float)(((temp_MSB << 8) + temp_LSB) >> 4);
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}
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else
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{
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ESP_LOGE(TAG, "ds18b20 device not responding");
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}
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}
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return temp;
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}
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