MSP430: Add "counter" driver

include/arch/msp430fr5969lp/driver/counter.h

+#include <msp430.h>
+#include <stdint.h>
+
+class Counter {
+	private:
+		Counter(const Counter &copy);
+
+	public:
+		uint8_t overflowed;
+
+		Counter() : overflowed(0) {}
+
+		inline void start() {
+			overflowed = 0;
+			TA2CTL = TASSEL__SMCLK | ID__1 | MC__CONTINUOUS;
+			TA2EX0 = 0;
+			TA2CTL |= TACLR;
+		}
+
+		inline uint16_t stop() {
+			TA2CTL = 0;
+			return TA2R;
+		}
+};
+
+extern Counter counter;

src/arch/msp430fr5969lp/Makefile.inc

@@ -49,6 +49,10 @@ ifneq ($(findstring timer,${arch_drivers}), )
 	CXX_TARGETS += src/arch/msp430fr5969lp/driver/timer.cc
 endif
 
+ifneq ($(findstring counter,${arch_drivers}), )
+	CXX_TARGETS += src/arch/msp430fr5969lp/driver/counter.cc
+endif
+
 ifneq (${cpu_freq}, )
 	COMMON_FLAGS += -DF_CPU=${cpu_freq}UL
 else

src/arch/msp430fr5969lp/driver/counter.cc

+#include "driver/counter.h"
+
+#if defined(TIMER_CYCLES)
+#warn "timer_cycles and counter are mutually exclusive. Expect odd behaviour."
+#endif
+
+Counter counter;