Add thread safety to Log class

README.md

@@ -1,2 +1,45 @@
 # resto-device
 Embedded project for resto card reader
+
+### Final application vision
+``` C
+// Clean code
+
+#include <Arduino.h>
+
+#include "Log.h"
+#include "Led.h"
+#include "Buzzer.h"
+#include "CardReader.h"
+
+#define MFRC522_RST_PIN          (5)
+#define MFRC522_SPI_SS_PIN       (10)
+#define MFRC522_IRQ_PIN          (1)
+#define BUZZER_PIN               (0)
+#define BUZZER_BEEP_DURATION_MS  (1000)
+#define GREEN_LED_ON_DURATION_MS (1000)
+
+static void onCardDetected(Card card);
+
+static const char *TAG = "MAIN";
+
+static CardReader cardReader(MFRC522_SPI_SS_PIN, MFRC522_RST_PIN, MFRC522_IRQ_PIN);
+static Buzzer buzzer(BUZZER_PIN);
+static Led greenLED(LED_GREEN);
+static Log logger(&Serial);
+
+void setup() {
+  logger.i(TAG, "App started...");
+
+  cardReader.registerCallback(onCardDetected);
+  cardReader.run();
+}
+
+void loop() {}
+
+static void onCardDetected(Card card) {
+  logger.i(TAG, "UID: " + card.getUID());
+  greenLED.asyncOn(GREEN_LED_ON_DURATION_MS);
+  buzzer.asyncOn(BUZZER_BEEP_DURATION_MS);
+}
+```

include/Log.h

@@ -3,6 +3,8 @@
 
 #include <Arduino.h>
 #include <stdarg.h>
+#include "FreeRTOS.h"
+#include "semphr.h"
 
 typedef struct {
   const char *level;
@@ -12,6 +14,7 @@ typedef struct {
 class Log {
 public:
   Log(HardwareSerial *serial);
+  void setup(unsigned long baudrate);
   void test(const char *tag, const char *format, ...);
   void d(const char *tag, const char *format, ...);
   void i(const char *tag, const char *format, ...);
@@ -20,6 +23,7 @@ class Log {
 
 private:
   HardwareSerial *_serial;
+  SemaphoreHandle_t _mutex;
   void printLog(const char *level, const char *tag, const char *format, va_list args);
   const char *getColor(const char *level);
 };

src/Log.cpp

@@ -1,18 +1,29 @@
 #include <Arduino.h>
 #include "Log.h"
-
-config_t config[] =
-{
-    {"TEST",    "\033[1;35m"},
-    {"DEBUG",   "\033[1;36m"},
-    {"INFO",    "\033[1;32m"},
-    {"WARNING", "\033[1;33m"},
-    {"ERROR",   "\033[1;31m"},
+#include "FreeRTOS.h"
+
+#define COLOR_MAGENTA "\033[1;35m"
+#define COLOR_CYAN    "\033[1;36m"
+#define COLOR_GREEN   "\033[1;32m"
+#define COLOR_YELLOW  "\033[1;33m"
+#define COLOR_RED     "\033[1;31m"
+
+const config_t config[] = {
+  {"TEST",    COLOR_MAGENTA},
+  {"DEBUG",   COLOR_CYAN   },
+  {"INFO",    COLOR_GREEN  },
+  {"WARNING", COLOR_YELLOW },
+  {"ERROR",   COLOR_RED    },
 };
 
 Log::Log(HardwareSerial *serial) {
   _serial = serial;
-  _serial->begin(115200);
+}
+
+void Log::setup(unsigned long baudrate) {
+  _serial->begin(baudrate);
+  while (!(_serial->availableForWrite()));
+  _mutex = xSemaphoreCreateMutex();
 }
 
 void Log::test(const char *tag, const char *format, ...) {
@@ -56,6 +67,8 @@ void Log::e(const char *tag, const char *format, ...) {
 }
 
 void Log::printLog(const char *level, const char *tag, const char *format, va_list args) {
+  xSemaphoreTake(_mutex, portMAX_DELAY);
+
   // Get the color associated with the level
   const char *color = getColor(level);
 
@@ -66,6 +79,8 @@ void Log::printLog(const char *level, const char *tag, const char *format, va_li
 
   // Reset color
   _serial->printf("\033[0m");
+
+  xSemaphoreGive(_mutex);
 }
 
 const char* Log::getColor(const char *level) {

src/main.cpp

@@ -22,7 +22,7 @@
 #define BUZZER_BEEP_DURATION_MS  (1000)
 #define BUZZER_TONE_FREQUENCY_HZ (1000)
 
-static void vTask1(void *pvParameters);
+static void cardReaderTask(void *pvParameters);
 static void vTask2(void *pvParameters);
 static void vTask3(void *pvParameters);
 
@@ -38,17 +38,33 @@ static volatile uint32_t detectionCounter = 0;
 const char *TAG = "MAIN";
 
 void setup() {
-  Serial.begin(SERIAL_BAUDRATE);
+  logger.setup(SERIAL_BAUDRATE);
 
-  xTaskCreate(vTask1, "Task 1", 1024, NULL, 1, NULL);
+  xTaskCreate(cardReaderTask, "Card Reader Task", 1024, NULL, 1, NULL);
   xTaskCreate(vTask2, "Task 2", 1024, NULL, 1, NULL);
   xTaskCreate(vTask3, "Task 3", 1024, NULL, 1, NULL);
 
+  vTaskStartScheduler();
+}
+
+void loop() {
+  delay(100);
+}
+
+void vApplicationStackOverflowHook(xTaskHandle *pxTask, signed portCHAR *pcTaskName) {
+  while (true);
+}
+
+static void cardReaderTask(void *pvParameters) {
+  const TickType_t xDelay = pdMS_TO_TICKS(100);
+  Led redLED(LED_RED);
+  byte byteIndex;
+
   SPI.begin();
   mfrc522.PCD_Init();
 
   // Read and printout the MFRC522 version (valid values are 0x91 and 0x92)
-  logger.i(TAG, "Version: 0x%X", mfrc522.PCD_ReadRegister(mfrc522.VersionReg));
+  logger.i(TAG, "MFRC522 version: 0x%X", mfrc522.PCD_ReadRegister(mfrc522.VersionReg));
 
   pinMode(MFRC522_IRQ_PIN, INPUT_PULLUP);
 
@@ -58,59 +74,35 @@ void setup() {
 
   attachInterrupt(digitalPinToInterrupt(MFRC522_IRQ_PIN), onCardDetected, FALLING);
 
-  vTaskStartScheduler();
-}
-
-void loop() {
-  byte byteIndex;
-
-  if (cardDetected) {
-    cardDetected = false;
-
-    // Once card is detected read its UID
-    logger.i(TAG, "Card detected");
-    logger.d(TAG, "detectionCounter: %lu\r\n", detectionCounter);
-    mfrc522.PICC_ReadCardSerial();
-    Serial.print(F("Card UID: "));
-    for (byteIndex = 0; byteIndex < mfrc522.uid.size; byteIndex++) {
-      Serial.print(mfrc522.uid.uidByte[byteIndex] < 0x10 ? " 0" : " ");
-      Serial.print(mfrc522.uid.uidByte[byteIndex], HEX);
+  logger.i(TAG, "Started Card Reader Task");
+  for(;;) {
+    if (cardDetected) {
+      cardDetected = false;
+
+      // Once card is detected read its UID
+      logger.i(TAG, "Card detected");
+      logger.d(TAG, "detectionCounter: %lu\r\n", detectionCounter);
+      mfrc522.PICC_ReadCardSerial();
+      Serial.print(F("Card UID: "));
+      for (byteIndex = 0; byteIndex < mfrc522.uid.size; byteIndex++) {
+        Serial.print(mfrc522.uid.uidByte[byteIndex] < 0x10 ? " 0" : " ");
+        Serial.print(mfrc522.uid.uidByte[byteIndex], HEX);
+      }
+      Serial.println();
+
+      // Clear pending interrupt
+      mfrc522.PCD_WriteRegister(mfrc522.ComIrqReg, 0x7F);
+      mfrc522.PICC_HaltA();
+
+      // Make a sound
+      buzzer.beep(BUZZER_BEEP_DURATION_MS);
     }
-    Serial.println();
-
-    // Clear pending interrupt
-    mfrc522.PCD_WriteRegister(mfrc522.ComIrqReg, 0x7F);
-    mfrc522.PICC_HaltA();
-
-    // Make a sound
-    buzzer.beep(BUZZER_BEEP_DURATION_MS);
-  }
-
-  // Activate reception
-  mfrc522.PCD_WriteRegister(mfrc522.FIFODataReg, mfrc522.PICC_CMD_REQA);
-  mfrc522.PCD_WriteRegister(mfrc522.CommandReg, mfrc522.PCD_Transceive);
-  mfrc522.PCD_WriteRegister(mfrc522.BitFramingReg, 0x87);
-
-  delay(100);
-}
-
-void vApplicationIdleHook(void) {
-  loop();
-}
-
-void vApplicationTickHook(void) {
-}
 
-void vApplicationStackOverflowHook(xTaskHandle *pxTask, signed portCHAR *pcTaskName) {
-  for(;;);
-}
+    // Activate reception
+    mfrc522.PCD_WriteRegister(mfrc522.FIFODataReg, mfrc522.PICC_CMD_REQA);
+    mfrc522.PCD_WriteRegister(mfrc522.CommandReg, mfrc522.PCD_Transceive);
+    mfrc522.PCD_WriteRegister(mfrc522.BitFramingReg, 0x87);
 
-static void vTask1(void *pvParameters) {
-  const TickType_t xDelay = pdMS_TO_TICKS(500);
-  Led redLED(LED_RED);
-
-  logger.i(TAG, "Started Task 1");
-  for(;;) {
     redLED.toggle();
     vTaskDelay(xDelay);
   }