system timer

r65emu.h

@@ -11,6 +11,7 @@
 #include "utftdisplay.h"
 #include "keyboard.h"
 #include "sdtape.h"
+#include "timed.h"
 #include "hardware.h"
 
 #endif

timed.cpp

@@ -0,0 +1,27 @@
+#include <Energia.h>
+#include <stdint.h>
+#include <inc/hw_ints.h>
+#include <driverlib/interrupt.h>
+#include <driverlib/sysctl.h>
+#include <driverlib/timer.h>
+
+#include "timed.h"
+
+static Timed *t;
+
+// FIXME: disable timer when tick() returns false
+static void timer0isr(void) {
+	ROM_TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
+	t->tick();
+}
+
+void timer_create(unsigned freq, Timed *client) {
+	t = client;
+	ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
+	ROM_TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC);
+	TimerIntRegister(TIMER0_BASE, TIMER_A, timer0isr);
+	ROM_TimerEnable(TIMER0_BASE, TIMER_A);
+	ROM_IntEnable(INT_TIMER0A);
+	ROM_TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
+	ROM_TimerLoadSet(TIMER0_BASE, TIMER_A, ROM_SysCtlClockGet() / freq);
+}

timed.h

@@ -0,0 +1,11 @@
+#ifndef __TIMED_H__
+#define __TIMED_H__
+
+class Timed {
+public:
+	virtual bool tick() = 0;
+};
+
+void timer_create(unsigned freq, Timed *client);
+
+#endif