1 files changed, 103 insertions, 0 deletions
diff --git a/recipes-demo/de10-nano-adxl-apps/files/tap_detect.c b/recipes-demo/de10-nano-adxl-apps/files/tap_detect.c
new file mode 100644
index 0000000..bbd19d1
--- /dev/null
+++ b/recipes-demo/de10-nano-adxl-apps/files/tap_detect.c
@@ -0,0 +1,103 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <error.h>
+#include <errno.h>
+#include <limits.h>
+#include <unistd.h>
+#include <string.h>
+#include "linux/input.h"
+
+#define INPUT_DEV_NODE "/dev/input/by-path/platform-ffc04000.i2c-event"
+#define SYSFS_DEVICE_DIR "/sys/devices/platform/soc/ffc04000.i2c/i2c-0/0-0053/"
+
+#define EV_CODE_X (0)
+#define EV_CODE_Y (1)
+#define EV_CODE_Z (2)
+
+#define LOOP_COUNT (100)
+
+void write_sysfs_cntl_file(const char *dir_name, const char *file_name,
+		const char *write_str) {
+
+	char path[PATH_MAX];
+	int path_length;
+	int file_fd;
+	int result;
+
+	// create the path to the file we need to open
+	path_length = snprintf(path, PATH_MAX, "%s/%s",	dir_name, file_name);
+	if(path_length < 0)
+		error(1, 0, "path output error");
+	if(path_length >= PATH_MAX)
+		error(1, 0, "path length overflow");
+
+	// open the file
+	file_fd = open(path, O_WRONLY | O_SYNC);
+	if(file_fd < 0)
+		error(1, errno, "could not open file '%s'", path);
+	
+	// write the string to the file
+	result = write(file_fd, write_str, strlen(write_str));
+	if(result < 0)
+		error(1, errno, "writing to '%s'", path);
+	if((size_t)(result) != strlen(write_str))
+		error(1, errno, "buffer underflow writing '%s'", path);
+
+	// close the file
+	result = close(file_fd);
+	if(result < 0)
+		error(1, errno, "could not close file '%s'", path);
+}
+
+int main(void) {
+	int event_dev_fd;
+	const char *input_dev_node = INPUT_DEV_NODE;
+	int result;
+	struct input_event the_event;
+
+	// enable adxl
+	write_sysfs_cntl_file(SYSFS_DEVICE_DIR, "disable", "0");
+
+	// set the sample rate to maximum
+	write_sysfs_cntl_file(SYSFS_DEVICE_DIR, "rate", "15");
+
+	// do not auto sleep
+	write_sysfs_cntl_file(SYSFS_DEVICE_DIR, "autosleep", "0");
+	
+	// open the event device node
+	event_dev_fd = open(input_dev_node, O_RDONLY | O_SYNC);
+	if(event_dev_fd < 0)
+		error(1, errno, "could not open file '%s'", input_dev_node);
+	
+	printf("Please tap the DE10 Nano board.\n");
+	
+	while(1) {
+		// read the next event
+		result = read(event_dev_fd, &the_event, 
+				sizeof(struct input_event));
+		if(result < 0)
+			error(1, errno, "reading %d from '%s'", 
+					sizeof(struct input_event),
+					input_dev_node);
+		if(result != sizeof(struct input_event))
+			error(1, 0, "did not read %d bytes from '%s'", 
+					sizeof(struct input_event),
+					input_dev_node);
+	
+		if((the_event.type == EV_KEY) && (the_event.code == BTN_TOUCH))
+			break;
+	}
+	
+	printf("Tap detected.\n");
+
+	// close the device node
+	result = close(event_dev_fd);
+	if(result < 0)
+		error(1, errno, "could not close file '%s'", input_dev_node);
+
+	// disable adxl
+	write_sysfs_cntl_file(SYSFS_DEVICE_DIR, "disable", "1");
+}
+