naming

Author: dizcza

README.md

@@ -9,3 +9,16 @@ To read the first three bytes (two for diff pressure and one CRC), it takes only
 
 See [sdpsensor-esp-arduino.ino](./sdpsensor-esp-arduino.ino).
 
+Serial output:
+
+```
+[  1021][I][sdpsensor.cpp:86] initI2C(): I2C0 line initialized
+[  1021][I][sdpsensor.cpp:204] reset(): SDPSensor::reset ESP_OK
+[  1042][I][sdpsensor.cpp:157] initSensor(): Initialized SDP31 500Pa sensor (PID=0x03010188)
+[  1133][I][sdpsensor.cpp:169] initSensor(): SDP31 pressure scale: 60
+[  1133][I][sdpsensor.cpp:182] startContinuous(): SDPSensor::startContinuous ESP_OK
+
+[  2154][I][sdpsensor-esp-arduino.ino:32] loop(): raw pressure: 0, err code: ESP_OK
+...
+```
+

sdpsensor-esp-arduino.ino

@@ -28,7 +28,7 @@ void setup() {
 void loop() {
   delay(1000);
   int16_t pressure;
-  esp_err_t err = sdp.readContinuousRaw(&pressure);
+  esp_err_t err = sdp.readDiffPressure(&pressure);
   ESP_LOGI("sdp", "raw pressure: %d, err code: %s", pressure, esp_err_to_name(err));
 
   /*

sdpsensor.cpp

@@ -25,10 +25,14 @@
 
 const char *TAG_SDPSENSOR = "sdpsensor";
 
-/*
+/**
+ * Compute CRC from data.
  * See http://www.sunshine2k.de/articles/coding/crc/understanding_crc.html
+ * 
+ * @param data - I2C read bytes of size 2
+ * @returns crc - the CRC value from the data
  */
-uint8_t SDPSensor::computeCRC(uint8_t* data)
+uint8_t computeCRC(uint8_t* data)
 {
     const uint8_t generator = 0x31;  /* Polynomial */
     uint8_t crc = 0xFF; /* Initial value from the datasheet */
@@ -114,7 +118,7 @@ void SDPSensor::initSensor() {
 	const uint32_t pid = (read_buffer[0] << 24) | (read_buffer[1] << 16)
 			| (read_buffer[3] << 8) | (read_buffer[4] << 0);
 
-    uint32_t model_number, range_pa;
+  uint32_t model_number, range_pa;
 	switch (pid & 0xFFFFFF00) {
 	case SPD31_500_PID:
 		model_number = 31;
@@ -232,7 +236,7 @@ void SDPSensor::watchdogCheck(esp_err_t status) {
 }
 
 
-esp_err_t SDPSensor::readContinuousRaw(int16_t *diffPressureRaw) {
+esp_err_t SDPSensor::readDiffPressure(int16_t *diffPressureRaw) {
 	uint8_t data[3] = { 0 };
 	esp_err_t err = i2c_master_read_from_device(i2c_port, i2c_addr, data, 3,
 			I2C_NO_TIMEOUT);
@@ -246,7 +250,7 @@ esp_err_t SDPSensor::readContinuousRaw(int16_t *diffPressureRaw) {
 }
 
 
-esp_err_t SDPSensor::readContinuousRawTemperature(int16_t *diffPressureRaw, float *temperature) {
+esp_err_t SDPSensor::readDiffPressureTemperature(int16_t *diffPressureRaw, float *temperature) {
 	uint8_t data[6] = { 0 };
 
 	/*

sdpsensor.h

@@ -16,9 +16,8 @@ class SDPSensor {
         uint8_t i2c_addr;                    /* I2C address */
         i2c_port_t i2c_port;                 /* I2C master port */
         uint16_t pressureScale;              /* Diff pressure scale */
-        uint32_t failsCount;                 /* SDP successive failed reads count */
-        uint32_t maxSuccessiveFailsCount;    /* SDP max successive failed reads before SW reset */
-        uint8_t computeCRC(uint8_t *data);   /* Compute CRC from data */
+        uint32_t failsCount;                 /* [watchdog] SDP successive failed reads count */
+        uint32_t maxSuccessiveFailsCount;    /* [watchdog] SDP max successive failed reads before SW reset */
     public:
 
         /**
@@ -76,6 +75,8 @@ class SDPSensor {
 
         /**
          * Reset the SDP sensor.
+         * All other sensors connected to the same I2C line
+         * (same port) will also receive the reset command.
          *
          * @returns the error code (defined in esp_err.h)
          */
@@ -106,10 +107,10 @@ class SDPSensor {
 
 
         /**
-         * Read the raw differential pressure value and save the result
-         * in `diffPressureRaw`. To convert it to the real value in Pa,
-         * one should divide it by the pressure scale (see
-         * `getPressureScale()` function).
+         * Read the raw (unnormalized) differential pressure value and
+         * save the result in `diffPressureRaw`. To convert it to a
+         * physical value in Pa, one should divide it by the pressure
+         * scale (see the `getPressureScale()` function).
          *
          * This call is non-blocking (zero I2C timeout).
          *
@@ -120,17 +121,19 @@ class SDPSensor {
          *    ESP_ERR_TIMEOUT      - timed out
          *    ESP_ERR_INVALID_CRC  - CRC mismatch
          */
-        esp_err_t readContinuousRaw(int16_t *diffPressureRaw);
+        esp_err_t readDiffPressure(int16_t *diffPressureRaw);
 
 
         /**
          * Read the raw differential pressure value AND the temperature.
          * 
+         * This call is non-blocking (zero I2C timeout).
+         * 
          * @param diffPressureRaw - a pointer to save the diff pressure
          * @param temperature - a pointer to save the temperature in Celsius
          * @returns the error code (defined in esp_err.h)
          */
-        esp_err_t readContinuousRawTemperature(int16_t *diffPressureRaw, float *temperature);
+        esp_err_t readDiffPressureTemperature(int16_t *diffPressureRaw, float *temperature);
 };
 
 #endif /* SDPSENSOR_H_ */