fix premature exit from ADC10 read caused by WDT_ISR

Author: RickKimball

hardware/msp430/cores/msp430/wiring_analog.c

@@ -157,39 +157,43 @@ void analogWrite(uint8_t pin, int val)
 
 uint16_t analogRead(uint8_t pin)
 {
-
 // make sure we have an ADC
 #if defined(__MSP430_HAS_ADC10__)
-	//	0000 A0
-	//	0001 A1
-	//	0010 A2
-	//	0011 A3
-	//	0100 A4
-	//	0101 A5
-	//	0110 A6
-	//	0111 A7
-	//	1010 Internal temperature sensor
-        
-        //TODO: Only int. temp. sensor requires Tsample > 30us.
-        // The below ADC configuration applies this rule to all channels right now.
-        // ADC10CLK = 5MHz / 5 = 1Mhz
-        // Tsample = S&H / ADC10CLK = 64 / 1 MHz = 64 us
-        // Tconver = 13 / ADC10CLK = 13 / 1 MHz = 13 us
-        // Total time per sample = Tconvert + Tsample = 64 + 13 = 67 us = ~15k samples / sec
-        if(pin > 7 && pin != 10)                        // ADC on pin?
-                return 0;
-	ADC10CTL0 &= ~ENC;                              // disable ADC
-	ADC10CTL0 = analog_reference +                  // set analog reference
-                    ADC10ON + ADC10SHT_3 + ADC10IE;     // turn ADC ON; sample + hold @ 64 × ADC10CLKs; Enable interrupts
-	ADC10CTL1 = ADC10SSEL_0 + ADC10DIV_5 +          // ADC10OSC as ADC10CLK (~5MHz) / 5 
-                        (pin << 12);                    // select channel
-	__delay_cycles (128);                           // Delay to allow Ref to settle
-	ADC10CTL0 |= ENC + ADC10SC;                     // enable ADC and start conversion
-	__bis_SR_register(CPUOFF + GIE);	        // LPM0 with interrupts enabled
-	return ADC10MEM;                                // return sampled value after returning to active mode in ADC10_ISR
+    //  0000 A0
+    //  0001 A1
+    //  0010 A2
+    //  0011 A3
+    //  0100 A4
+    //  0101 A5
+    //  0110 A6
+    //  0111 A7
+    //  1010 Internal temperature sensor
+
+    //TODO: Only int. temp. sensor requires Tsample > 30us.
+    // The below ADC configuration applies this rule to all channels right now.
+    // ADC10CLK = 5MHz / 5 = 1Mhz
+    // Tsample = S&H / ADC10CLK = 64 / 1 MHz = 64 us
+    // Tconvert = 13 / ADC10CLK = 13 / 1 MHz = 13 us
+    // Total time per sample = Tconvert + Tsample = 64 + 13 = 67 us = ~15k samples / sec
+    if (pin > 7 && pin != 10) {             // Is this a valid ADC pin?
+        return 0;
+    }
+
+    ADC10CTL0 &= ~ENC;                      // disable ADC
+    ADC10CTL0 = analog_reference |          // set analog reference
+            ADC10ON | ADC10SHT_3 | ADC10IE; // turn ADC ON; sample + hold @ 64 × ADC10CLKs; Enable interrupts
+    ADC10CTL1 = ADC10SSEL_0 | ADC10DIV_5 |  // ADC10OSC as ADC10CLK (~5MHz) / 5
+            (pin << 12);                    // select channel
+    __delay_cycles(128);                    // Delay to allow Ref to settle
+    ADC10CTL0 |= ENC | ADC10SC;             // enable ADC and start conversion
+    while (ADC10CTL1 & ADC10BUSY) {         // sleep and wait for completion
+        __bis_SR_register(CPUOFF + GIE);    // LPM0 with interrupts enabled
+    }
+
+    return ADC10MEM;             // return sampled value after returning to active mode in ADC10_ISR
 #else
-	// no ADC
-	return 0;
+    // no ADC
+    return 0;
 #endif
 }