Added a Makefile that will produce ./lib/<MCU>/liblowpower.a files.

.gitignore

@@ -0,0 +1 @@
+lib

LowPower.cpp

@@ -660,10 +660,10 @@ void	LowPowerClass::idle(period_t period, adc_t adc, timer5_t timer5,
 void	LowPowerClass::adcNoiseReduction(period_t period, adc_t adc, 
 										 timer2_t timer2)
 {
-	// Temporary clock source variable 
-	unsigned char clockSource = 0;
-
 	#if !defined(__AVR_ATmega32U4__)
+	// Temporary clock source variable
+	unsigned char clockSource = 0;
+
 	if (timer2 == TIMER2_OFF)
 	{
 		if (TCCR2B & CS22) clockSource |= (1 << CS22);
@@ -804,10 +804,10 @@ void	LowPowerClass::powerDown(period_t period, adc_t adc, bod_t bod)
 void	LowPowerClass::powerSave(period_t period, adc_t adc, bod_t bod, 
 							     timer2_t timer2)
 {
-	// Temporary clock source variable 
+	#if !defined(__AVR_ATmega32U4__)
+	// Temporary clock source variable
 	unsigned char clockSource = 0;
 
-	#if !defined(__AVR_ATmega32U4__)
 	if (timer2 == TIMER2_OFF)
 	{
 		if (TCCR2B & CS22) clockSource |= (1 << CS22);
@@ -948,10 +948,10 @@ void	LowPowerClass::powerStandby(period_t period, adc_t adc, bod_t bod)
 void	LowPowerClass::powerExtStandby(period_t period, adc_t adc, bod_t bod, 
 									   timer2_t timer2)
 {
-	// Temporary clock source variable 
-	unsigned char clockSource = 0;
-
 	#if !defined(__AVR_ATmega32U4__)
+	// Temporary clock source variable
+	unsigned char clockSource = 0;
+
 	if (timer2 == TIMER2_OFF)
 	{
 		if (TCCR2B & CS22) clockSource |= (1 << CS22);

LowPower.h

@@ -1,8 +1,6 @@
 #ifndef LowPower_h
 #define LowPower_h
 
-#include "Arduino.h"
-
 enum period_t
 {
 	SLEEP_15MS,

Makefile

@@ -0,0 +1,62 @@
+#   A Makefile that will produce a ./lib/<MCU>/liblowpower.a file per supported MCU.
+#   Copyright (C) 2018  Pieter du Preez <[email protected]>
+#
+#	This program is free software: you can redistribute it and/or modify
+#	it under the terms of the GNU General Public License as published by
+#	the Free Software Foundation, either version 3 of the License, or
+#	(at your option) any later version.
+#
+#	This program is distributed in the hope that it will be useful,
+#	but WITHOUT ANY WARRANTY; without even the implied warranty of
+#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#	GNU General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License
+#	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# NOTE: All libs will be compiled with an 8MHz clock,
+#       unless CPU_FREQ is set at make-time.
+# eg. overriding all mcus to 16Mhz:
+#       CPU_FREQ=16000000L make clean all
+
+CPU_FREQ ?= 8000000L
+
+# NOTE: The atsamd21g18a is not supported by this Makefile.
+SUPPORTED_MCUS = \
+atmega168 \
+atmega328p \
+atmega32u4 \
+atmega2560 \
+atmega256rfr2
+
+# Default to the standard Linux tool paths.
+TOOLCHAIN_PATH ?= /usr/bin
+
+CC = $(abspath $(TOOLCHAIN_PATH))/avr-gcc
+CXX = $(abspath $(TOOLCHAIN_PATH))/avr-g++
+AR = $(abspath $(TOOLCHAIN_PATH))/avr-ar
+SIZE = $(abspath $(TOOLCHAIN_PATH))/avr-size
+
+TARGETS = $(addprefix lib/,$(addsuffix /liblowpower.a,$(SUPPORTED_MCUS)))
+SIZES = $(addsuffix _size,$(SUPPORTED_MCUS))
+
+# The following line is a work-around for issue #14:
+atmega168_DEFINES = -DSLEEP_MODE_EXT_STANDBY=SLEEP_MODE_STANDBY
+
+all: $(TARGETS)
+
+%_dir:
+	mkdir -p lib/$*
+
+lib/%/liblowpower.a: lib/%/LowPower.o
+	$(AR) -r $@ $<
+	$(MAKE) $*_size
+
+%_size: lib/%/liblowpower.a
+	$(SIZE) --format=avr --mcu=$* lib/$*/liblowpower.a
+
+lib/%/LowPower.o: LowPower.cpp LowPower.h %_dir
+	$(CXX) -c -std=c++11 -pedantic -fverbose-asm -Werror -Os -I$(AVR_INCLUDE) -DF_CPU=$(CPU_FREQ) $($*_DEFINES) -mmcu=$* -o $@ $<
+
+clean:
+	rm -rf lib