Add support for ATmega2560, ATmega1280. Closes #1.

README.md

@@ -20,7 +20,7 @@ Since each call to `read()` measures only a single cycle, it may be desirable, d
 
 Because measuring AC causes the current transformer to output positive and negative currents, a DC bias must be applied to ensure that below-ground voltages are not applied to the microcontroller's ADC input. It is also necessary to ensure that peak voltages do not exceed the microcontroller's supply voltage (Vcc). Do the math to ensure that your circuit operates within safe limits; also see the example below.
 
-This library is specific to the AVR microcontroller architecture and will not work on others. Timer/Counter1 is used to trigger the ADC conversions and so is not available for other purposes.
+This library is specific to the AVR microcontroller architecture and will not work on others. Only ATmega328/P, ATmega1280 and ATmega2560 are supported. Timer/Counter1 is used to trigger the ADC conversions and so is not available for other purposes.
 
 ## Example Design Calculations
 

library.properties

@@ -1,5 +1,5 @@
 name=CurrentTransformer
-version=2.2.2
+version=2.3.0
 author=Jack Christensen <[email protected]>
 maintainer=Jack Christensen <[email protected]>
 sentence=Arduino Library for measuring current in 50/60Hz circuits using current transformers.

src/CurrentTransformer.cpp

@@ -8,13 +8,18 @@
 CT_Sensor::CT_Sensor(uint8_t channel, float ratio, float burden)
     : m_ratio(ratio), m_burden(burden)
 {
-    if (channel >= 14) channel -= 14;   // if user passed A0-A5, adjust accordingly
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    if (channel >= 54) channel -= 54;   // if user passed pin number, convert to channel number
+    m_channel = channel & 0x0f;         // ruthlessly coerce to an acceptable value
+#else
+    if (channel >= 14) channel -= 14;   // if user passed pin number, convert to channel number
     m_channel = channel & 0x07;         // ruthlessly coerce to an acceptable value
+#endif
 }
 
-volatile bool CT_Control::adcBusy;
-volatile int CT_Control::adcVal;
-const uint16_t CT_Control::sampleSize(65);   // number of samples to cover one cycle
+volatile  bool CT_Control::adcBusy;
+volatile   int CT_Control::adcVal;
+const uint16_t CT_Control::sampleSize(65);  // number of samples to cover one cycle
 const uint16_t CT_Control::ADC_MAX(1023);
 const uint16_t CT_Control::OCR50(F_CPU / 50 / CT_Control::sampleSize / 2 - 1);
 const uint16_t CT_Control::OCR60(F_CPU / 60 / CT_Control::sampleSize / 2 - 1);
@@ -32,13 +37,17 @@ float CT_Control::begin()
     ADCSRA = _BV(ADEN) | _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0);  // default adc configuration
     ADCSRB = 0;
     // set AVcc as reference, 1.1V bandgap reference voltage as input
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+#else
     ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+#endif
     delay(10);                              // Vref settling time
     ADCSRA |= _BV(ADSC);                    // start conversion
     loop_until_bit_is_clear(ADCSRA, ADSC);  // wait for it to complete
     int mv = 1125300L / ADC;                // calculate AVcc in mV (1.1 * 1000 * 1023)
     m_vcc = static_cast<float>(mv) / 1000.0;
-    
+
     // set up the timer
     TCCR1B = 0;                             // stop the timer
     TCCR1A = 0;
@@ -54,7 +63,7 @@ float CT_Control::begin()
     // set up the adc
     ADCSRA  = _BV(ADEN)  | _BV(ADATE) | _BV(ADIE);      // enable ADC, auto trigger, interrupt when conversion complete
     ADCSRA |= _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0);     // ADC clock prescaler: divide by 128 (for 125kHz)
-    ADCSRB = _BV(ADTS2) | _BV(ADTS0);                   // trigger ADC on Timer/Counter1 Compare Match B    
+    ADCSRB = _BV(ADTS2) | _BV(ADTS0);                   // trigger ADC on Timer/Counter1 Compare Match B
 
     return m_vcc;
 }
@@ -73,32 +82,44 @@ void CT_Control::end()
 
 void CT_Control::read(CT_Sensor *ct0, CT_Sensor *ct1)
 {
-    uint8_t n(0);                       // sample count
-    int32_t sumsq0(0), sumsq1(0);       // sum of squares
-    ADMUX = _BV(REFS0) | ct0->m_channel; // set channel, and AVcc as reference
-    while (!adcBusy);                   // wait for one conversion
+    uint8_t n(0);                               // sample count
+    int32_t sumsq0(0), sumsq1(0);               // sum of squares
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    if (ct0->m_channel > 7) {ADCSRB |= _BV(MUX5);}
+    else {ADCSRB &= !_BV(MUX5);}
+#endif
+    ADMUX = _BV(REFS0) | (ct0->m_channel & 0x07);   // set channel, and AVcc as reference
+    while (!adcBusy);                               // wait for one conversion
     while (adcBusy);
 
     do
     {
         // read ct0
-        ADMUX = _BV(REFS0) | ct0->m_channel;    // set channel, and AVcc as reference
-        while (!adcBusy);                       // wait for next conversion to start
-        while (adcBusy);                        // wait for conversion to complete
-        int32_t v0 = adcVal;                    // get the reading, promote to 32 bit
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+        if (ct0->m_channel > 7) {ADCSRB |= _BV(MUX5);}
+        else {ADCSRB &= !_BV(MUX5);}
+#endif
+        ADMUX = _BV(REFS0) | (ct0->m_channel & 0x07);   // set channel, and AVcc as reference
+        while (!adcBusy);                               // wait for next conversion to start
+        while (adcBusy);                                // wait for conversion to complete
+        int32_t v0 = adcVal;                            // get the reading, promote to 32 bit
 
         // read ct1
-        ADMUX = _BV(REFS0) | ct1->m_channel;    // set channel, and AVcc as reference
-        while (!adcBusy);                       // wait for next conversion to start
-        while (adcBusy);                        // wait for conversion to complete
-        int32_t v1 = adcVal;                    // get the reading, promote to 32 bit
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+        if (ct1->m_channel > 7) {ADCSRB |= _BV(MUX5);}
+        else {ADCSRB &= !_BV(MUX5);}
+#endif
+        ADMUX = _BV(REFS0) | (ct1->m_channel & 0x07);   // set channel, and AVcc as reference
+        while (!adcBusy);                               // wait for next conversion to start
+        while (adcBusy);                                // wait for conversion to complete
+        int32_t v1 = adcVal;                            // get the reading, promote to 32 bit
 
         // accumulate the sum of squares,
         // subtract 512 (half the adc range) to remove dc component
         sumsq0 += (v0 - ADC_MAX/2) * (v0 - ADC_MAX/2);
         sumsq1 += (v1 - ADC_MAX/2) * (v1 - ADC_MAX/2);
     } while (++n < sampleSize);
-    
+
     // calculate rms voltage and current
     float Vrms0 = m_vcc * sqrt(static_cast<float>(sumsq0) / static_cast<float>(sampleSize - 1)) / ADC_MAX;
     float Vrms1 = m_vcc * sqrt(static_cast<float>(sumsq1) / static_cast<float>(sampleSize - 1)) / ADC_MAX;