1 files changed, 48 insertions, 0 deletions
diff --git a/fw/tests/system/speed_systest.c b/fw/tests/system/speed_systest.c
new file mode 100644
index 0000000..72fb271
--- /dev/null
+++ b/fw/tests/system/speed_systest.c
@@ -0,0 +1,48 @@
+#include <xc.h>
+
+#include <stdint.h>
+
+#include "system.h"
+#include "types.h"
+
+// (pulse/min) = 60 * (Fosc/4) / ((pre)*(post)*(PR2+1)*(period))
+// = 60 * (48e6/4) / (64*16*10*(period))
+// = 70313 / (period)
+#define SPEED_FACTOR 70313ul
+#define MIN_SPEED_PULSE_PER_MIN 2u // (pulse/min) >= SPEED_FACTOR / period_max)
+#define EDGE_PER_PULSE 2u // rising and falling edge
+
+static volatile U16 tmr2Period = 0u;
+
+void
+main(void) {
+	sysInit();
+
+	U16 pulsePerMin = 550u;
+	tmr2Period = ((U32)SPEED_FACTOR / pulsePerMin) & 0xFFFF;
+
+	T2CON = 0x7F; // postscaler=1:16, enable=1, prescaler=1:64
+	PR2 = 10u-1u; // period = PR2+1
+
+	INTCON = 0x00;
+	PIE1bits.TMR2IE = 1;
+	INTCONbits.PEIE = 1;
+	INTCONbits.GIE = 1;
+
+	for (;;) {
+
+	}
+}
+
+void __interrupt()
+isr(void) {
+	static U16 tmr2Ctr = 0u;
+
+	if (TMR2IF) { // speedometer
+		if (++tmr2Ctr >= (tmr2Period/EDGE_PER_PULSE)) {
+			tmr2Ctr = 0u;
+			SPEED_PIN ^= 1; // toggle speedometer output
+		}
+		TMR2IF = 0;
+	}
+}