add support for temperature reading functions

README.md

@@ -125,6 +125,7 @@ Where:
 * ```transmit_fsk``` - TX in FSK mode. Variable packet length, NRZ encoding, CRC, AFC on. Sending several messages: small 2 byte, messages that can fit into FIFO fully, max messages for variable packet type - 255 bytes and same messages, but for node address 0x11 and 0x00.
 * ```transmit_fsk_fixed``` - TX in FSK mode. Fixed packet length - 2047 bytes, NRZ encoding, CRC, AFC on.
 * ```transmit_ook``` - TX in OOK mode. Variable packet length, NRZ encoding, CRC, AFC on. Sending several messages: small 2 byte, messages that can fit into FIFO fully, max messages for variable packet type - 255 bytes and same messages, but for node address 0x11 and 0x00.
+* ```temperature``` - Constantly read raw temperature value from the internal sensor. Must be calibrated first using well-known temperature. Available in FSK mode.
 
 # Tests
 

examples/temperature/CMakeLists.txt

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.5)
+
+set(EXTRA_COMPONENT_DIRS "../../")
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(sx127x_temperature)
+

examples/temperature/main/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRCS "main.c" INCLUDE_DIRS "")

examples/temperature/main/main.c

@@ -0,0 +1,70 @@
+#include <driver/spi_common.h>
+#include <driver/spi_master.h>
+#include <esp_log.h>
+#include <freertos/task.h>
+#include <sx127x.h>
+#include <rom/ets_sys.h>
+
+// TTGO lora32 v2.1 1.6.1
+#define SCK 5
+#define MISO 19
+#define MOSI 27
+#define SS 18
+#define RST 23
+#define DIO0 26
+// older versions of TTGO require manual wiring of pins below
+#define DIO1 33
+#define DIO2 32
+
+// Heltec lora32 v2
+// #define DIO1 35
+// #define DIO2 34
+
+static const char *TAG = "sx127x";
+
+sx127x *device = NULL;
+
+void app_read_temperature() {
+  ESP_ERROR_CHECK(sx127x_set_opmod(SX127x_MODE_FSRX, SX127x_MODULATION_FSK, device));
+  //enable temp monitoring
+  ESP_ERROR_CHECK(sx127x_fsk_ook_set_temp_monitor(true, device));
+  // a little bit longer for FSRX mode to kick off
+  ets_delay_us(150);
+  //disable temp monitoring
+  ESP_ERROR_CHECK(sx127x_fsk_ook_set_temp_monitor(false, device));
+  ESP_ERROR_CHECK(sx127x_set_opmod(SX127x_MODE_SLEEP, SX127x_MODULATION_FSK, device));
+
+  int8_t raw_temperature;
+  ESP_ERROR_CHECK(sx127x_fsk_ook_get_raw_temperature(device, &raw_temperature));
+  ESP_LOGI(TAG, "raw temperature: %d", raw_temperature);
+}
+
+void app_main() {
+  ESP_LOGI(TAG, "starting up");
+  spi_bus_config_t config = {
+      .mosi_io_num = MOSI,
+      .miso_io_num = MISO,
+      .sclk_io_num = SCK,
+      .quadwp_io_num = -1,
+      .quadhd_io_num = -1,
+      .max_transfer_sz = 0,
+  };
+  ESP_ERROR_CHECK(spi_bus_initialize(HSPI_HOST, &config, 1));
+  spi_device_interface_config_t dev_cfg = {
+      .clock_speed_hz = 3E6,
+      .spics_io_num = SS,
+      .queue_size = 16,
+      .command_bits = 0,
+      .address_bits = 8,
+      .dummy_bits = 0,
+      .mode = 0};
+  spi_device_handle_t spi_device;
+  ESP_ERROR_CHECK(spi_bus_add_device(HSPI_HOST, &dev_cfg, &spi_device));
+  ESP_ERROR_CHECK(sx127x_create(spi_device, &device));
+  ESP_ERROR_CHECK(sx127x_set_opmod(SX127x_MODE_SLEEP, SX127x_MODULATION_FSK, device));
+
+  while (1) {
+    app_read_temperature();
+    vTaskDelay(pdMS_TO_TICKS(5000));
+  }
+}

include/sx127x.h

@@ -903,6 +903,26 @@ int sx127x_fsk_ook_rx_set_preamble_detector(bool enable, uint8_t detector_size,
  */
 int sx127x_fsk_ook_rx_calibrate(sx127x *device);
 
+/**
+ * @brief Control temperature monitoring. By default enabled. Should be used to measure the temperature in any mode except Sleep and Standby
+ * @param enable - Default: enabled
+ * @param device Pointer to variable to hold the device handle
+ * @return int
+ *         - SX127X_ERR_INVALID_STATE if current state is not STANDBY
+ *         - SX127X_OK                on success
+ */
+int sx127x_fsk_ook_set_temp_monitor(bool enable, sx127x *device);
+
+/**
+ * @brief Higher precision requires a calibration procedure at a known temperature.
+ * @param device Pointer to variable to hold the device handle
+ * @param raw_temperature raw sensor temperature. Due to process variations, the absolute accuracy of the result is +/- 10 °C.
+ * @return int
+ *         - SX127X_ERR_INVALID_STATE if current state is not STANDBY
+ *         - SX127X_OK                on success
+ */
+int sx127x_fsk_ook_get_raw_temperature(sx127x *device, int8_t *raw_temperature);
+
 /**
  * @brief Disconnect from SPI and release any resources assotiated. After calling this function pointer to device will be unusable.
  *

src/sx127x.c

@@ -80,6 +80,7 @@
 #define REG_SYNC_WORD 0x39
 #define REG_INVERTIQ2 0x3b
 #define REG_IMAGE_CAL 0x3b
+#define REG_TEMP 0x3c
 #define REG_IRQ_FLAGS_1 0x3e
 #define REG_IRQ_FLAGS_2 0x3f
 #define REG_DIO_MAPPING_1 0x40
@@ -1210,6 +1211,25 @@ int sx127x_fsk_ook_rx_calibrate(sx127x *device) {
   return SX127X_OK;
 }
 
+int sx127x_fsk_ook_get_raw_temperature(sx127x *device, int8_t *raw_temperature) {
+  CHECK_FSK_OOK_MODULATION(device);
+  uint8_t value;
+  ERROR_CHECK(sx127x_read_register(REG_TEMP, device->spi_device, &value));
+  if ((value & 0x80) == 0x80) {
+    *raw_temperature = 255 - value;
+  } else {
+    *raw_temperature = -1 * value;
+  }
+  return SX127X_OK;
+}
+
+int sx127x_fsk_ook_set_temp_monitor(bool enable, sx127x *device) {
+  CHECK_FSK_OOK_MODULATION(device);
+  // the field is called TempMonitorOff, thus inverted
+  uint8_t value = (enable ? 0b00000000 : 0b00000001);
+  return sx127x_append_register(REG_IMAGE_CAL, value, 0b11111110, device->spi_device);
+}
+
 void sx127x_destroy(sx127x *device) {
   if (device == NULL) {
     return;