arduino-nano: Add counter driver. Conflicts with timer_s=1 / loop=1

include/arch/arduino-nano/driver/counter.h

+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+class Counter {
+	private:
+		Counter(const Counter &copy);
+
+	public:
+		uint8_t overflowed;
+
+		Counter() : overflowed(0) {}
+
+		inline void start() {
+			overflowed = 0;
+			TCNT1 = 0;
+			TCCR1A = 0;
+			TCCR1B = _BV(CS10);
+			TIMSK1 = _BV(TOIE1);
+		}
+
+		inline uint16_t stop() {
+			TCCR1B = 0;
+			return TCNT1;
+		}
+};
+
+extern Counter counter;

src/arch/arduino-nano-168/Makefile.inc

@@ -40,6 +40,10 @@ ifneq ($(findstring timer,${arch_drivers}), )
 	CXX_TARGETS += src/arch/arduino-nano/driver/timer.cc
 endif
 
+ifneq ($(findstring counter,${arch_drivers}), )
+	CXX_TARGETS += src/arch/arduino-nano/driver/counter.cc
+endif
+
 ifeq (${cpu_freq}, 16000000)
 	uart_baud = 57600
 else ifeq (${cpu_freq}, 8000000)

src/arch/arduino-nano/Makefile.inc

@@ -40,6 +40,10 @@ ifneq ($(findstring timer,${arch_drivers}), )
 	CXX_TARGETS += src/arch/arduino-nano/driver/timer.cc
 endif
 
+ifneq ($(findstring counter,${arch_drivers}), )
+	CXX_TARGETS += src/arch/arduino-nano/driver/counter.cc
+endif
+
 ifeq (${cpu_freq}, 16000000)
 	uart_baud = 57600
 else ifeq (${cpu_freq}, 8000000)

src/arch/arduino-nano/driver/counter.cc

+#include "driver/counter.h"
+
+Counter counter;
+
+ISR(TIMER1_OVF_vect)
+{
+	if (counter.overflowed < 255) {
+		counter.overflowed++;
+	}
+}