mirror of
https://github.com/espressif/esp-idf.git
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107 lines
3.9 KiB
C
107 lines
3.9 KiB
C
/*
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* SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Unlicense OR CC0-1.0
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*/
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#include <string.h>
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#include "ds18b20.h"
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#include "esp_check.h"
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static const char *TAG = "ds18b20";
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esp_err_t ds18b20_trigger_temperature_conversion(onewire_bus_handle_t handle, const uint8_t *rom_number)
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{
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ESP_RETURN_ON_FALSE(handle, ESP_ERR_INVALID_ARG, TAG, "invalid 1-wire handle");
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ESP_RETURN_ON_ERROR(onewire_bus_reset(handle), TAG, "error while resetting bus"); // reset bus and check if the device is present
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uint8_t tx_buffer[10];
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uint8_t tx_buffer_size;
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if (rom_number) { // specify rom id
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tx_buffer[0] = ONEWIRE_CMD_MATCH_ROM;
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tx_buffer[9] = DS18B20_CMD_CONVERT_TEMP;
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memcpy(&tx_buffer[1], rom_number, 8);
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tx_buffer_size = 10;
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} else { // skip rom id
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tx_buffer[0] = ONEWIRE_CMD_SKIP_ROM;
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tx_buffer[1] = DS18B20_CMD_CONVERT_TEMP;
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tx_buffer_size = 2;
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}
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ESP_RETURN_ON_ERROR(onewire_bus_write_bytes(handle, tx_buffer, tx_buffer_size),
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TAG, "error while triggering temperature convert");
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return ESP_OK;
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}
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esp_err_t ds18b20_get_temperature(onewire_bus_handle_t handle, const uint8_t *rom_number, float *temperature)
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{
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ESP_RETURN_ON_FALSE(handle, ESP_ERR_INVALID_ARG, TAG, "invalid 1-wire handle");
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ESP_RETURN_ON_FALSE(temperature, ESP_ERR_INVALID_ARG, TAG, "invalid temperature pointer");
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ESP_RETURN_ON_ERROR(onewire_bus_reset(handle), TAG, "error while resetting bus"); // reset bus and check if the device is present
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ds18b20_scratchpad_t scratchpad;
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uint8_t tx_buffer[10];
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uint8_t tx_buffer_size;
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if (rom_number) { // specify rom id
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tx_buffer[0] = ONEWIRE_CMD_MATCH_ROM;
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tx_buffer[9] = DS18B20_CMD_READ_SCRATCHPAD;
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memcpy(&tx_buffer[1], rom_number, 8);
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tx_buffer_size = 10;
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} else {
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tx_buffer[0] = ONEWIRE_CMD_SKIP_ROM;
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tx_buffer[1] = DS18B20_CMD_READ_SCRATCHPAD;
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tx_buffer_size = 2;
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}
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ESP_RETURN_ON_ERROR(onewire_bus_write_bytes(handle, tx_buffer, tx_buffer_size),
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TAG, "error while sending read scratchpad command");
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ESP_RETURN_ON_ERROR(onewire_bus_read_bytes(handle, (uint8_t *)&scratchpad, sizeof(scratchpad)),
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TAG, "error while reading scratchpad command");
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ESP_RETURN_ON_FALSE(onewire_check_crc8((uint8_t *)&scratchpad, 8) == scratchpad.crc_value, ESP_ERR_INVALID_CRC,
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TAG, "crc error");
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static const uint8_t lsb_mask[4] = { 0x07, 0x03, 0x01, 0x00 };
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uint8_t lsb_masked = scratchpad.temp_lsb & (~lsb_mask[scratchpad.configuration >> 5]); // mask bits not used in low resolution
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*temperature = (((int16_t)scratchpad.temp_msb << 8) | lsb_masked) / 16.0f;
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return ESP_OK;
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}
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esp_err_t ds18b20_set_resolution(onewire_bus_handle_t handle, const uint8_t *rom_number, ds18b20_resolution_t resolution)
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{
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ESP_RETURN_ON_FALSE(handle, ESP_ERR_INVALID_ARG, TAG, "invalid 1-wire handle");
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ESP_RETURN_ON_ERROR(onewire_bus_reset(handle), TAG, "error while resetting bus"); // reset bus and check if the device is present
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uint8_t tx_buffer[10];
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uint8_t tx_buffer_size;
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if (rom_number) { // specify rom id
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tx_buffer[0] = ONEWIRE_CMD_MATCH_ROM;
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tx_buffer[9] = DS18B20_CMD_WRITE_SCRATCHPAD;
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memcpy(&tx_buffer[1], rom_number, 8);
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tx_buffer_size = 10;
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} else {
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tx_buffer[0] = ONEWIRE_CMD_SKIP_ROM;
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tx_buffer[1] = DS18B20_CMD_WRITE_SCRATCHPAD;
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tx_buffer_size = 2;
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}
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ESP_RETURN_ON_ERROR(onewire_bus_write_bytes(handle, tx_buffer, tx_buffer_size),
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TAG, "error while sending read scratchpad command");
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tx_buffer[0] = 0;
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tx_buffer[1] = 0;
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tx_buffer[2] = resolution;
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ESP_RETURN_ON_ERROR(onewire_bus_write_bytes(handle, tx_buffer, 3),
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TAG, "error while sending write scratchpad command");
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return ESP_OK;
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}
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