Add frequency scanning to PWM loop tests

quad/vivado_workspace/PWM_Combined_Tests/PWM_Combined_Tests.sdk/Loopback_Error_Check/src/helloworld.c

@@ -51,6 +51,7 @@
 #include "xparameters.h"
 #include "xuartps.h"
 #include "sleep.h"
+#include "math.h"
 
 int main() {
 	init_platform();
@@ -61,33 +62,43 @@ int main() {
 			(volatile uint32_t*) (XPAR_PWM_RECORDER_0_S_AXI_BASEADDR);
 	volatile uint32_t* pwmGenerate =
 			(volatile uint32_t*) (XPAR_PWM_SIGNAL_OUT_0_S_AXI_BASEADDR);
+	while (1) {
+		print(
+				"Please connect JB0 and JB1 with an external jumper.\r\nWhen ready, press any button.\n\r");
+		while (buttonsGPIO[0] == 0)
+			;
+		print("Thank You :)\r\n");
 
-	print(
-			"Please connect JB0 and JB1 with an external jumper.\r\nWhen ready, press any button.\n\r");
-	while (buttonsGPIO[0] == 0)
-		;
-	print("Thank You :)\r\n");
+		const int min_period = 1000;
+		const int max_period = 5 * 1000 * 1000;
+		const float period_step_factor = 1.5;
+		int period;
+		for (period = min_period; period < max_period; period *=
+				period_step_factor) {
 
-	pwmGenerate[0] = 50 * 1000;
-	pwmGenerate[1] = 25 * 1000;
+			pwmGenerate[1] = period / 2;
+			pwmGenerate[0] = period;
 
-	int iteration;
-	const int num_iterations = 100;
-	for (iteration = 0; iteration < num_iterations; iteration++) {
-		pwmGenerate[1] = (iteration * pwmGenerate[0]) / num_iterations;
-		usleep(10000);
+			int duty_iteration;
+			const int num_duty_iterations = 100;
+			for (duty_iteration = 0; duty_iteration < num_duty_iterations;
+					duty_iteration++) {
+				pwmGenerate[1] = ((duty_iteration + 1) * pwmGenerate[0])
+						/ (num_duty_iterations + 1);
 
-		int error = pwmRecord[0] - pwmGenerate[1];
-		int abserror = error;
-		if (abserror < 0) {
-			abserror = -error;
+				usleep(period / 25);
+
+				int error = pwmRecord[0] - pwmGenerate[1];
+				int abserror = (error < 0) ? -error : error;
+				if (abserror > pwmGenerate[0] / 1000) {
+					xil_printf("%5d Hz, %3d%% Duty Cycle: %d cycle error\r\n",
+							(50 * 1000 * 1000 / pwmGenerate[0]),
+							(100 * pwmGenerate[1]) / pwmGenerate[0], error);
+				}
+
+			}
+			usleep(period / 5);
 		}
-		xil_printf("%3d%% Duty Cycle: %c%3d.%08d%% error\r\n",
-				(100 * pwmGenerate[1]) / pwmGenerate[0],
-				(error < 0) ? '-' : ' ',
-				(100 * abserror) / ((int) pwmGenerate[0]),
-				((10000000000 * abserror) / ((int) pwmGenerate[0]))
-						% 100000000);
 	}
 	cleanup_platform();
 	return 0;