Merge pull request #5 from blemasle/features-optional-pins

Reduce required pin count

README.md

@@ -2,7 +2,7 @@
 [![Build Status](https://travis-ci.org/blemasle/arduino-sim808.svg?branch=master)](https://travis-ci.org/blemasle/arduino-sim808)
 [![License](https://img.shields.io/badge/license-MIT%20License-blue.svg)](http://doge.mit-license.org)
 
-This library allows to access some of the features of the [SIM808](https://simcom.ee/documents/?dir=SIM808) GPS & GPRS module. It requires at least 3 pins (power, status and reset pins) to work and a TTL Serial.
+This library allows to access some of the features of the [SIM808](https://simcom.ee/documents/?dir=SIM808) GPS & GPRS module. It requires only the `RESET` pin to work and a TTL Serial. `STATUS` pin can be wired to enhance the module power status detection, while wiring the `PWRKEY` adds the ability to turn the module on & off.
 
 The library tries to reduces memory consumption as much as possible, but nonetheless use a 64 bytes buffer to communicate with the SIM808 module. When available, SIM808 responses are parsed to ensure that commands are correctly executed by the module. Commands timeouts are also set according to SIMCOM documentation.  
 
@@ -46,17 +46,19 @@ It does *not* have the pretention to become the new SIM808 standard library, but
 
 SoftwareSerial simSerial = SoftwareSerial(SIM_TX, SIM_RX)
 SIM808 sim808 = SIM808(SIM_RST, SIM_PWR, SIM_STATUS);
+// SIM808 sim808 = SIM808(SIM_RST); // if you only have the RESET pin wired
+// SIM808 sim808 = SIM808(SIM_RST, SIM_PWR); // if you only have the RESET and PWRKEY pins wired
 
 void setup() {
     simSerial.begin(SIM808_BAUDRATE);
     sim808.begin(simSerial);
 
-    sim808.powerOnOff(true);    //power on the SIM808
+    sim808.powerOnOff(true);    //power on the SIM808. Unavailable without the PWRKEY pin wired
     sim808.init();
 }
 
 void loop() {
-    //whatever you need to do
+    // whatever you need to do
 }
  ```
 See examples for further usage.

examples/Tester/Tester.ino

@@ -171,7 +171,7 @@ void power() {
             return;
         }
 
-        Log.notice(S_F("%s : %S"), buffer, status ? TO_F(ON) : TO_F(OFF));
+        Log.notice(S_F("%s : %S" NL), buffer, status ? TO_F(ON) : TO_F(OFF));
     }
     else if(BUFFER_IS_P(ON)) {
         readNext();

library.properties

@@ -1,5 +1,5 @@
 name=SIM808
-version=1.0.1
+version=1.1.0
 author=Bertrand Lemasle
 maintainer=Bertrand Lemasle
 sentence=Straightforward Arduino library for the SIM808

src/SIM808.Power.cpp

@@ -5,14 +5,21 @@ TOKEN_TEXT(CFUN, "+CFUN");
 
 bool SIM808::powered()
 {
+	if(_statusPin == SIM808_UNAVAILABLE_PIN) {
+		sendAT();
+		return waitResponse(SIMCOMAT_DEFAULT_TIMEOUT) != -1;
+	}
+
 	return digitalRead(_statusPin) == HIGH;
 }
 
 bool SIM808::powerOnOff(bool power)
 {
+	if (_pwrKeyPin == SIM808_UNAVAILABLE_PIN) return false;
+
 	bool currentlyPowered = powered();
 	if (currentlyPowered == power) return false;
-
+	
 	SIM808_PRINT_P("powerOnOff: %t", power);
 
 	digitalWrite(_pwrKeyPin, LOW);

src/SIM808.cpp

@@ -2,17 +2,17 @@
 
 TOKEN(RDY);
 
-SIM808::SIM808(uint8_t resetPin, uint8_t pwrKeyPin, uint8_t statusPin)
+SIM808::SIM808(uint8_t resetPin, uint8_t pwrKeyPin = SIM808_UNAVAILABLE_PIN, uint8_t statusPin = SIM808_UNAVAILABLE_PIN)
 {
 	_resetPin = resetPin;
 	_pwrKeyPin = pwrKeyPin;
 	_statusPin = statusPin;
 
 	pinMode(_resetPin, OUTPUT);
-	pinMode(_pwrKeyPin, OUTPUT);
-	pinMode(_statusPin, INPUT);
+	if(_pwrKeyPin != SIM808_UNAVAILABLE_PIN) pinMode(_pwrKeyPin, OUTPUT);
+	if (_statusPin != SIM808_UNAVAILABLE_PIN) pinMode(_statusPin, INPUT);
 
-	digitalWrite(_pwrKeyPin, HIGH);
+	if(_pwrKeyPin != SIM808_UNAVAILABLE_PIN) digitalWrite(_pwrKeyPin, HIGH);
 	digitalWrite(_resetPin, HIGH);
 }
 

src/SIM808.h

@@ -5,6 +5,7 @@
 
 #define HTTP_TIMEOUT 10000L
 #define GPS_ACCURATE_FIX_MIN_SATELLITES 4
+#define SIM808_UNAVAILABLE_PIN 255
 
 class SIM808 : public SIMComAT
 {
@@ -52,16 +53,18 @@ class SIM808 : public SIMComAT
 	bool setBearerSetting(ATConstStr parameter, const char* value);
 
 public:
-	SIM808(uint8_t resetPin, uint8_t pwrKeyPin, uint8_t statusPin);
+	SIM808(uint8_t resetPin, uint8_t pwrKeyPin = SIM808_UNAVAILABLE_PIN, uint8_t statusPin = SIM808_UNAVAILABLE_PIN);
 	~SIM808();	
 
 	/**
 	 * Get a boolean indicating wether or not the device is currently powered on.
+	 * The power state is read from either the statusPin if set, or from a test AT command response.
 	 */
 	bool powered();
 	/**
 	 * Power on or off the device only if the requested state is different than the actual state.
-	 * Returns true if the power state has been changed has a result of this call.
+	 * Returns true if the power state has been changed as a result of this call.
+	 * Unavailable and returns false in all cases if pwrKeyPin is not set.
 	 * 
 	 * See powered()
 	 */