initial implementation of analogWrite

Only tested using Fading sketch on Launchpad LED2

hardware/msp430/cores/msp430/Energia.h

@@ -47,13 +47,18 @@ extern "C"{
 #define P6 6
 #define P7 7
 
-#define TIMER0A 1
-#define TIMER0B 2
-#define TIMER1A 3
-#define TIMER1B 4
-#define TIMER2  5
-#define TIMER2A 6
-#define TIMER2B 7
+#define T0A0 0
+#define T0A1 1
+#define T0A2 2
+#define T1A0 3
+#define T1A1 4
+#define T1A2 5
+#define T1A3 6
+#define T1A4 7
+#define T1A5 8
+#define T2A0 9
+#define T2A1 10
+#define T2A1 11
 
 typedef uint8_t boolean;
 typedef uint8_t byte;
@@ -94,16 +99,26 @@ void pinMode(uint8_t, uint8_t);
 void digitalWrite(uint8_t, uint8_t);
 int digitalRead(uint8_t);
 uint16_t analogRead(uint8_t);
+void analogWrite(uint8_t, int);
 void analogReference(uint16_t);
 
 void delay(uint32_t milliseconds);
 
 void attachInterrupt(uint8_t, void (*)(void), int mode);
 void detachInterrupt(uint8_t);
 
+extern const uint8_t digital_pin_to_timer[];
+extern const uint8_t digital_pin_to_port[];
+extern const uint8_t digital_pin_to_bit_mask[];
+extern const uint16_t port_to_sel[];
+extern const uint16_t port_to_sel2[];
+
 #define digitalPinToPort(P) ( digital_pin_to_port[P] )
 #define digitalPinToBitMask(P) ( digital_pin_to_bit_mask[P] )
+#define digitalPinToTimer(P) ( digital_pin_to_timer[P] )
 #define portDirRegister(P) ( (volatile uint16_t *)( port_to_dir[P]) )
+#define portSelRegister(P) ( (volatile uint16_t *)( port_to_sel[P]) )
+#define portSel2Register(P) ( (volatile uint16_t *)( port_to_sel2[P]) )
 #define portOutputRegister(P) ( (volatile uint16_t *)( port_to_output[P]) )
 #define portInputRegister(P) ( (volatile uint16_t *)( port_to_input[P]) )
 #define digitalPinToTimer(P) ( digital_pin_to_timer[P] )

hardware/msp430/cores/msp430/wiring_analog.c

@@ -42,15 +42,81 @@ void analogReference(uint16_t mode)
 	analog_reference = mode;
 }
 
-/*
- * TODO: make this interrupt based so that we can wait in LPM0
- */
+//TODO: Can be a lot more efficient.
+//      - lower clock rated / input divider to conserve Energia.
+//      - pin configuration logic.
+//Arduino specifies ~490 Hz for analog out PWM so we follow suit.
+#define PWM_PERIOD F_CPU/490
+#define PWM_DUTY PWM_PERIOD / 255
+void analogWrite(uint8_t pin, int val)
+{
+        pinMode(pin, OUTPUT); // pin as output
+
+ 	if (val == 0)
+	{
+		digitalWrite(pin, LOW); // set pin to LOW when duty cycle is 0
+                                        // digitalWrite will take care of invalid pins
+	}
+	else if (val == 255)
+	{
+		digitalWrite(pin, HIGH); // set pin HIGH when duty cycle is 255
+                                         // digitalWrite will take care of invalid pins
+	}
+	else
+	{
+
+	        uint8_t bit = digitalPinToBitMask(pin); // get pin bit
+	        uint8_t port = digitalPinToPort(pin);   // get pin port
+	        volatile uint16_t *sel;
+	        volatile uint16_t *sel2;
+
+                if (port == NOT_A_PORT) return; // pin on timer?
+
+	        sel = portSelRegister(port); // get the port function select register address
+		*sel |= bit;                 // set bit in pin function select register  
+
+                //TODO: Firgure out a way to determine if SEL2 needs to be set
+	        //reg2 = portSel2Register(port); // get the port function select register address
+
+                switch(digitalPinToTimer(pin)) {                // which timer and CCR?
+ 			//case: T0A0                            // CCR0 used as period register
+			case T0A1:                              // Timer0 / CCR1
+                                TA0CCR0 = PWM_PERIOD;           // PWM Period
+                                TA0CCTL1 = OUTMOD_7;            // reset/set
+                                TA0CCR1 = PWM_DUTY * val;       // PWM duty cycle
+                                TA0CTL = TASSEL_2 + MC_1;       // SMCLK, up mode
+                                break;
+ 			case T0A2:                              // Timer0 / CCR1
+                                TA0CCR0 = PWM_PERIOD;           // PWM Period
+                                TA0CCTL2 = OUTMOD_7;            // reset/set
+                                TA0CCR2 = PWM_DUTY * val;       // PWM duty cycle
+                                TA0CTL = TASSEL_2 + MC_1;       // SMCLK, up mode
+                                break;
+#if defined(__MSP430_HAS_T1A3__) 
+                        case T1A0:
+                        case T1A1:
+                        case T1A2:
+#endif
+#if defined(__MSP430_HAS_T2A3__) 
+                        case T2A0:
+                        case T2A1:
+                        case T2A2:
+#endif
+                        case NOT_ON_TIMER:
+			default:
+				if (val < 128) {
+					digitalWrite(pin, LOW);
+				} else {
+					digitalWrite(pin, HIGH);
+				}
+                }
+        }
+}
+
 uint16_t analogRead(uint8_t pin)
 {
 
 // make sure we have an ADC
-	// Pin has ADC functionality?
-
 #if defined(__MSP430_HAS_ADC10__)
 	//	0000 A0
 	//	0001 A1
@@ -62,6 +128,7 @@ uint16_t analogRead(uint8_t pin)
 	//	0111 A7
 	//	1010 Internal temperature sensor
 
+        // Pin has ADC functionality?
 	if(pin > 7 && pin != 10)
 		return 0;
 

hardware/msp430/variants/launchpad/pins_arduino.h

@@ -47,7 +47,6 @@ static const uint8_t A7 = 7;
 static const uint8_t A10 = 10; // special. This is the internal temp sensor
 
 #ifdef ARDUINO_MAIN
-
 //                      +-\/-+
 //               VCC   1|    |28  GND
 //         (A0)  P1.0  2|    |27  XIN
@@ -71,6 +70,24 @@ const uint16_t port_to_dir[] = {
 #endif
 };
 
+const uint16_t port_to_sel[] = {
+	NOT_A_PORT,
+	(uint16_t) &P1SEL,
+	(uint16_t) &P2SEL,
+#ifdef __MSP430_HAS_PORT3_R__
+	(uint16_t) &P3SEL,
+#endif
+};
+
+const uint16_t port_to_sel2[] = {
+	NOT_A_PORT,
+	(uint16_t) &P1SEL2,
+	(uint16_t) &P2SEL2,
+#ifdef __MSP430_HAS_PORT3_R__
+	(uint16_t) &P3SEL2,
+#endif
+};
+
 const uint16_t port_to_input[] = {
 	NOT_A_PORT,
 	(uint16_t) &P1IN,
@@ -88,27 +105,32 @@ const uint16_t port_to_output[] = {
 #endif
 };
 
-const uint8_t digital_pin_to_port[] = {
-	NOT_A_PIN, /* 0 */
-	NOT_A_PIN, /* 1 */
-	P1, /* 2 */
-	P1, /* 3 */
-	P1, /* 4 */
-	P1, /* 5 */
-	P1, /* 6 */
-	P1, /* 7 */
-	P2, /* 8 */
-	P2, /* 9 */
-	P2, /* 10 */
-	P2, /* 11 */
-	P2, /* 12 */
-	P2, /* 13 */
-	P1, /* 14 */
-	P1, /* 15 */
+const uint8_t digital_pin_to_timer[] = {
+	NOT_ON_TIMER, /*  dummy */
+	NOT_ON_TIMER, /*  1 - VCC */
+	NOT_ON_TIMER, /*  2 - P1.0 */
+	T0A0,         /*  3 - P1.1 */
+	T0A1,         /*  4 - P1.2 */
+	NOT_ON_TIMER, /*  5 - P1.3 */
+//only g-series with 2 timers and comp have TA0.2 on P1.4??
+#if defined(__MSP430_HAS_T1A3__) && defined(__MSP430_HAS_CAPLUS__) 
+	T0A2,         /*  6 - P1.4 */
+#else
+	NOT_ON_TIMER, /*  6 - P1.4 */
+#endif
+	T0A0,         /*  7 - P1.5 */
+	NOT_ON_TIMER, /*  8 - P2.0 */
+	NOT_ON_TIMER, /*  9 - P2.1 */
+	NOT_ON_TIMER, /* 10 - P2.3 */
+	NOT_ON_TIMER, /* 11 - P2.4 */
+	NOT_ON_TIMER, /* 12 - P2.5 */
+	NOT_ON_TIMER, /* 13 - P2.6 */
+	T0A1,         /* 14 - P1.6 */
+	NOT_ON_TIMER, /* 15 - P1.7 */
 };
 
-const uint8_t digital_pin_to_timer[] = {
-	NOT_A_PIN, /* 0 */
+const uint8_t digital_pin_to_port[] = {
+	NOT_A_PIN, /* dummy */
 	NOT_A_PIN, /* 1 */
 	P1, /* 2 */
 	P1, /* 3 */