--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main/task_ds18b20.c Tue Oct 08 12:00:31 2019 +0200
@@ -0,0 +1,152 @@
+/**
+ * @file task_ds18b20.c
+ * @brief The FreeRTOS task to query the DS18B20 sensors on one or two
+ * one-wire busses. Each bus must have only one sensor. That way
+ * we don't need to care about the DS18B20 internal ROM address.
+ * The task will update the DS18B20_State structure.
+ */
+
+
+#include "owb.h"
+#include "owb_rmt.h"
+#include "ds18b20.h"
+#include "config.h"
+
+
+#define GPIO_DS18B20_BUS (CONFIG_ONE_WIRE_BUS)
+#define MAX_DEVICES (8)
+#define DS18B20_RESOLUTION (DS18B20_RESOLUTION_12_BIT)
+#define SAMPLE_PERIOD (2000) // milliseconds
+
+
+static const char *TAG = "task_ds18b20";
+static const char *dsErrors[] = { "Ok", "No sensor", "Too many sensors", "CRC error", "Read error" };
+
+SemaphoreHandle_t xSemaphoreDS18B20 = NULL; ///< Semaphire DS18B20 task
+EventGroupHandle_t xEventGroupDS18B20; ///< Events DS18B20 task
+DS18B20_State *ds18b20_state; ///< Public state for other tasks
+
+
+const int TASK_DS18B20_REQUEST_TEMPS = BIT0; ///< Request temperature measurements
+const int TASK_DS18B20_REQUEST_DONE = BIT1; ///< Request is completed
+
+
+
+void request_ds18b20(void)
+{
+ xEventGroupClearBits(xEventGroupDS18B20, TASK_DS18B20_REQUEST_DONE);
+ xEventGroupSetBits(xEventGroupDS18B20, TASK_DS18B20_REQUEST_TEMPS);
+}
+
+
+
+bool ready_ds18b20(void)
+{
+ if (xEventGroupGetBits(xEventGroupDS18B20) & TASK_DS18B20_REQUEST_DONE)
+ return true;
+ return false;
+}
+
+
+
+/*
+ * Task to read temperature sensors on request.
+ */
+void task_ds18b20(void *pvParameter)
+{
+ int num_devices = 0;
+ float readings = 0;
+ bool found = false;
+ DS18B20_ERROR errors = 0;
+
+ ESP_LOGI(TAG, "Starting DS18B20 sensors");
+ ds18b20_state = malloc(sizeof(DS18B20_State));
+ ds18b20_state->bottle_valid = false;
+ ds18b20_state->bottle_temperature = 0.0;
+ ds18b20_state->bottle_error = DS18B20_ERR_NOSENSOR;
+
+ /* event handler and event group for the wifi driver */
+ xEventGroupDS18B20 = xEventGroupCreate();
+
+ /*
+ * Initialize the MLT and HLT one-wire busses.
+ */
+ OneWireBus *owb_bottle;
+ owb_rmt_driver_info rmt_driver_info_bottle;
+ owb_bottle = owb_rmt_initialize(&rmt_driver_info_bottle, GPIO_DS18B20_BUS, RMT_CHANNEL_1, RMT_CHANNEL_0);
+ owb_use_crc(owb_bottle, true); // enable CRC check for ROM code
+
+ DS18B20_Info * ds18b20_info = ds18b20_malloc();
+ EventBits_t uxBits;
+
+ /*
+ * Task loop forever.
+ */
+ while (1) {
+
+ uxBits = xEventGroupWaitBits(xEventGroupDS18B20, TASK_DS18B20_REQUEST_TEMPS, pdFALSE, pdFALSE, portMAX_DELAY );
+
+ if (uxBits & TASK_DS18B20_REQUEST_TEMPS) {
+ num_devices = 0;
+ OneWireBus_SearchState bottle_search_state = {0};
+ found = false;
+ owb_search_first(owb_bottle, &bottle_search_state, &found);
+ while (found) {
+ ++num_devices;
+ owb_search_next(owb_bottle, &bottle_search_state, &found);
+ }
+
+ if (num_devices == 1) {
+ ds18b20_init_solo(ds18b20_info, owb_bottle); // only one device on bus
+ ds18b20_use_crc(ds18b20_info, true); // enable CRC check for temperature readings
+ ds18b20_set_resolution(ds18b20_info, DS18B20_RESOLUTION); // returns true if ok.
+
+ // Read temperatures more efficiently by starting conversions on all devices at the same time
+ ds18b20_convert_all(owb_bottle);
+ ds18b20_wait_for_conversion(ds18b20_info);
+
+ errors = ds18b20_read_temp(ds18b20_info, &readings);
+
+ if (xSemaphoreTake(xSemaphoreDS18B20, 25) == pdTRUE) {
+ if (errors == DS18B20_OK) {
+ ds18b20_state->bottle_error = DS18B20_ERR_NONE;
+ ds18b20_state->bottle_valid = true;
+ ds18b20_state->bottle_temperature = readings;
+ } else {
+ if (errors == DS18B20_ERROR_CRC)
+ ds18b20_state->bottle_error = DS18B20_ERR_CRC;
+ if (errors == DS18B20_ERROR_OWB)
+ ds18b20_state->bottle_error = DS18B20_ERR_READ;
+ if (errors == DS18B20_ERROR_DEVICE)
+ ds18b20_state->bottle_error = DS18B20_ERR_READ;
+ ds18b20_state->bottle_valid = false;
+ ds18b20_state->bottle_temperature = 0.0;
+ }
+ xSemaphoreGive(xSemaphoreDS18B20);
+ }
+
+ } else {
+ /*
+ * Zero or more then one device, this is an error.
+ */
+ if (xSemaphoreTake(xSemaphoreDS18B20, 25) == pdTRUE) {
+ if (num_devices == 0)
+ ds18b20_state->bottle_error = DS18B20_ERR_NOSENSOR;
+ else
+ ds18b20_state->bottle_error = DS18B20_ERR_TOOMANY;
+ ds18b20_state->bottle_valid = false;
+ ds18b20_state->bottle_temperature = 0.0;
+ xSemaphoreGive(xSemaphoreDS18B20);
+ }
+ } // if num_devices == 1
+
+ xEventGroupClearBits(xEventGroupDS18B20, TASK_DS18B20_REQUEST_TEMPS);
+ xEventGroupSetBits(xEventGroupDS18B20, TASK_DS18B20_REQUEST_DONE);
+#if 1
+ ESP_LOGI(TAG, "Temperature %.3f %s", ds18b20_state->bottle_temperature, dsErrors[ds18b20_state->bottle_error]);
+#endif
+ }
+ vTaskDelay( (TickType_t)10);
+ }
+}
+