Add missing files.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

src/board.h

@@ -0,0 +1,33 @@
+/*
+ * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
+ * Copyright (c) 2022 Pol Henarejos.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _BOARD_H_
+#define _BOARD_H_
+
+#ifdef _MSC_VER
+#include <windows.h>
+#else
+#include <sys/time.h>
+#endif
+
+static inline uint32_t board_millis() {
+    struct timeval start;
+    gettimeofday(&start, NULL);
+    return start.tv_sec * 1000 + start.tv_usec / 1000;
+}
+
+#endif // _BOARD_H_