Bug fixes and support for powering down modules

.gitignore

@@ -1,3 +1,6 @@
+.pioenvs
+.clang_complete
+.gcc-flags.json
 *.bin
 *.eep
 *.elf
@@ -12,3 +15,4 @@ libcore.a
 .clang_complete
 .gcc-flags.json
 .piolibdeps
+

.library.json

@@ -0,0 +1,22 @@
+{
+    "name": "Interrupted",
+	"authors":
+	[
+		{
+			"name": "Stephen Crane",
+			"email": "jscrane@gmail.com",
+			"url": "https://www.linkedin.com/in/jscrane",
+            "maintainer": true
+		}
+	],
+    "version" : "1.1.0",
+    "description" : "Interrupt driven device framework",
+    "keywords" : "avr, Arduino",
+    "repository":
+    {
+            "type" : "git",
+            "url": "https://github.com/jscrane/Interrupted.git"
+    },
+    "frameworks": ["arduino"],
+    "platforms": ["atmelavr"]
+}

.travis.yml

@@ -0,0 +1,65 @@
+# Continuous Integration (CI) is the practice, in software
+# engineering, of merging all developer working copies with a shared mainline
+# several times a day < http://docs.platformio.org/en/stable/ci/index.html >
+#
+# Documentation:
+#
+# * Travis CI Embedded Builds with PlatformIO
+#   < https://docs.travis-ci.com/user/integration/platformio/ >
+#
+# * PlatformIO integration with Travis CI
+#   < http://docs.platformio.org/en/stable/ci/travis.html >
+#
+# * User Guide for `platformio ci` command
+#   < http://docs.platformio.org/en/stable/userguide/cmd_ci.html >
+#
+#
+# Please choice one of the following templates (proposed below) and uncomment
+# it (remove "# " before each line) or use own configuration according to the
+# Travis CI documentation (see above).
+#
+
+
+#
+# Template #1: General project. Test it using existing `platformio.ini`.
+#
+
+# language: python
+# python:
+#     - "2.7"
+#
+# sudo: false
+# cache:
+#     directories:
+#         - "~/.platformio"
+#
+# install:
+#     - pip install -U platformio
+#
+# script:
+#     - platformio run
+
+
+#
+# Template #2: The project is intended to by used as a library with examples
+#
+
+# language: python
+# python:
+#     - "2.7"
+#
+# sudo: false
+# cache:
+#     directories:
+#         - "~/.platformio"
+#
+# env:
+#     - PLATFORMIO_CI_SRC=path/to/test/file.c
+#     - PLATFORMIO_CI_SRC=examples/file.ino
+#     - PLATFORMIO_CI_SRC=path/to/test/directory
+#
+# install:
+#     - pip install -U platformio
+#
+# script:
+#     - platformio ci --lib="." --board=ID_1 --board=ID_2 --board=ID_N

analog.h

@@ -1,16 +1,19 @@
 #ifndef __ANALOG_H__
 #define __ANALOG_H__
 
+#include <Arduino.h>
+#include "device.h"
+
 /**
  * Analog-to-Digital conversion.
- * 
+ *
  * FIXME: analogReadResolution()
  */
 class Analog: public Device {
 public:
 	// pin is the analog input, e.g., A0-A7
 	Analog(int pin, unsigned ref = DEFAULT):
-		Device(pin), _pin(pin), _ref(ref) {}
+		Device(pin), _pin(pin), _ref(ref), _next_reading_valid(false) {}
 
 	// not enabled by default
 	bool begin();
@@ -24,6 +27,13 @@ class Analog: public Device {
 	// returns last converted value or 0xffff if not ready
 	unsigned read();
 
+	// call to turn off ADC altogether and back on again
+	virtual void sleep();
+	virtual void wake();
+
+	bool next_reading_valid(void) {return _next_reading_valid;}
+	void next_reading_will_be_valid() {_next_reading_valid = true; }
+
 protected:
 	void _enable(bool enabled);
 
@@ -33,6 +43,7 @@ class Analog: public Device {
 
 	int _pin;
 	unsigned _ref;
+	volatile bool _next_reading_valid;
 };
 
 #endif

atmega328p/analog.cpp

@@ -6,15 +6,22 @@
 #include "device.h"
 #include "analog.h"
 
-static Device *adc;
+static Analog *adc;
 static volatile unsigned reading = 0xffff;
 
 ISR(ADC_vect) {
 	if (adc) {
 		uint8_t low = ADCL;
 		uint8_t high = ADCH;
 		reading = (high << 8) | low;
-		adc->ready();
+		if (adc->_next_reading_valid)
+			adc->ready();
+		else
+		{
+			// Can't use this conversion so start a new conversion
+			ADCSRA |= bit(ADSC) | bit(ADIE);
+			adc->_next_reading_valid = true;
+		}
 	}
 }
 
@@ -39,13 +46,24 @@ void Analog::_init() {
 	ADMUX = (_ref << 6) | ((_pin - A0) & 0x0f);
 }
 
+void Analog::sleep() {
+	ADCSRA &= ~_BV(ADEN);
+	ACSR |= _BV(ACD);
+	power_adc_disable();
+}
+
+void Analog::wake() {
+	power_adc_enable();
+	_next_reading_valid = false;  // Ignore first reading after power on
+	ADCSRA |= _BV(ADEN);
+	ACSR &= ~_BV(ACD);
+}
+
 bool Analog::begin() {
 	adc = this;
 	unsigned sreg = SREG;
 	cli();
-	power_adc_enable();
-	ADCSRA |= _BV(ADEN);
-	ACSR &= ~_BV(ACD);
+	wake();
 	_init();
 	SREG = sreg;
 	return false;

atmega328p/device.cpp

@@ -6,6 +6,10 @@
 
 #include "device.h"
 
+// Ensure that these are defined properly (there appears to be a bug in avr/power.h for ATMega328[P])
+#define power_all_enable()      (PRR &= (uint8_t)~((1<<PRADC)|(1<<PRTIM0)|(1<<PRTIM1)|(1<<PRTIM2)|(1<<PRSPI)|(1<<PRTWI)|(1<<PRUSART0)))
+#define power_all_disable()     (PRR |= (uint8_t)((1<<PRADC)|(1<<PRTIM0)|(1<<PRTIM1)|(1<<PRTIM2)|(1<<PRSPI)|(1<<PRTWI)|(1<<PRUSART0)))
+
 void Devices::begin() {
 	// "...[it] is therefore required to turn off the watchdog
 	// early during program startup..." (from avr/wdt.h)
@@ -14,6 +18,9 @@ void Devices::begin() {
 	// turn off ADC and analog comparator
 	ADCSRA &= ~bit(ADEN);
 	ACSR |= bit(ACD);
+
+
+	// power down all modules until they are needed
 	power_all_disable();
 
 	// turn off the brown-out detector
@@ -23,7 +30,13 @@ void Devices::begin() {
 		digitalWrite(i, LOW);
 
 	for (int i = 0; i < _n; i++)
-		_devices[i]->enable(_devices[i]->begin());
+	{
+		if (_devices[i]->begin())
+		{
+			_devices[i]->wake();
+			_devices[i]->enable(true);
+		}
+	}
 
 	sei();
 }

atmega328p/serial.cpp

@@ -1,24 +1,38 @@
 #include <avr/io.h>
-#include <avr/sleep.h>
 #include <avr/power.h>
+#include <avr/sleep.h>
 #include <avr/interrupt.h>
+#include <Arduino.h>
 
 #include "device.h"
 #include "serial.h"
 
 void SerialDevice::init() {
 	if (_baud) {
-		power_usart0_enable();
 		unsigned prescale = ((F_CPU) / 16 + (_baud / 2)) / _baud - 1;
-		uint8_t sreg = SREG;
-		cli();
+
+		uint8_t saved_SREG = SREG;	// Save the interrupt flag
+		cli();				// disable interrupts while initializing the USART
 		UBRR0H = (prescale >> 8) & 0xff;
 		UBRR0L = prescale & 0xff;
-		UCSR0C = _BV(UCSZ00) | _BV(UCSZ01);	// 8N1
-		SREG = sreg;
+		UCSR0C = bit(UCSZ00) | bit(UCSZ01);  // 8 bits, no parity, 1 stop bit
+		SREG = saved_SREG;	// restore the interrupt flag
 	}
 }
 
 unsigned SerialDevice::_sleepmode() {
 	return SLEEP_MODE_IDLE;
 }
+
+// call to turn off device altogether
+void SerialDevice::sleep()
+{
+	power_usart0_disable(); // Power down the USART
+}
+
+// call to turn device on again
+void SerialDevice::wake()
+{
+	power_usart0_enable();	// Ensure USART powered up
+	this->init(); 			// After power on, the module must be initialized
+}

atmega328p/serialin.cpp

@@ -10,7 +10,8 @@ static SerialIn *device;
 
 bool SerialIn::begin() {
 	device = this;
-	init();
+	wake();
+  sleep();
 	return true;
 }
 

atmega328p/serialout.cpp

@@ -1,4 +1,5 @@
 #include <avr/io.h>
+#include <avr/power.h>
 #include <avr/sleep.h>
 #include <avr/interrupt.h>
 #include <Arduino.h>
@@ -11,8 +12,9 @@ static SerialOut *device;
 
 bool SerialOut::begin() {
 	device = this;
-	init();
+	wake();
 	UCSR0B |= _BV(TXEN0);
+  sleep();
 	return false;
 }
 
@@ -30,10 +32,13 @@ bool SerialOut::write(char const *ptr) {
 	return false;
 }
 
+// Output a single character; may be called from interrupt service routine
+// If no more characters, then signal that the device is ready
 void SerialOut::do_output() {
 	byte b = *_tx_ptr;
 	if (b) {
 		_tx_ptr++;
+		bitClear(UCSR0B, TXC0);
 		UDR0 = b;
 	} else {
 		_tx_ptr = 0;
@@ -47,3 +52,4 @@ ISR(USART_TX_vect)
 	if (device)
 		device->do_output();
 }
+

atmega328p/timer.cpp

@@ -1,27 +1,52 @@
 #include <avr/io.h>
+#include <avr/power.h>
 #include <avr/sleep.h>
 #include <avr/power.h>
 #include <avr/interrupt.h>
 
 #include "device.h"
 #include "timer.h"
 
+// Timer 1 is used so as to avoid conflict with the timer 0, used by the delay() function in the Arduino library
 static Device *t1;
 
+// Ensure that these are defined properly
+#ifndef power_timer1_enable
+#define power_timer1_enable()   (PRR &= (uint8_t)~(1 << PRTIM1))
+#endif
+#ifndef power_timer1_disable
+#define power_timer1_disable()  (PRR |= (uint8_t)(1 << PRTIM1))
+#endif
+
 ISR(TIMER1_COMPA_vect) {
 	if (t1)
 		t1->ready();
 }
 
+// call to turn off device altogether
+void Timer::sleep()
+{
+	power_timer1_disable();
+}
+
+// call to turn device on again
+void Timer::wake()
+{
+	power_timer1_enable();
+}
+
+
 bool Timer::begin() {
 	t1 = this;
+
 	power_timer1_enable();
 
 	TCCR1A = 0;
 	// CTC mode, 1024 prescaler
 	TCCR1B = _BV(WGM12) | _BV(CS10) | _BV(CS12);
 
-	OCR1A = F_CPU / 1024000 - 1;	// 1 ms
+	OCR1A = (uint16_t) (F_CPU / 1024000L) - 1; // approximately 1 ms divided by the divisor
+	sleep();
 	return false;
 }
 
@@ -34,9 +59,9 @@ void Timer::_enable(bool e) {
 	else
 		TIMSK1 &= ~_BV(OCIE1A);
 	SREG = sreg;
+
 }
 
 unsigned Timer::_sleepmode() {
 	return SLEEP_MODE_IDLE;
 }
-

atmega328p/watchdog.cpp

@@ -26,7 +26,7 @@ void Watchdog::_enable(bool e) {
 	cli();
 	uint8_t b = 0;
 	if (e) {
-		wdt_reset();
+		wdt_reset();  // Ensure that the timer will start from 0 again
 		b = _BV(WDIE) | _scale;
 	}
 	WDTCSR = _BV(WDCE) | _BV(WDE);