add template for main screen and buttons, need menu etc

F3:F303/NitrogenFlooding/buttons.h

@@ -0,0 +1,40 @@
+/*
+ * This file is part of the nitrogen project.
+ * Copyright 2023 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * 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, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/>.
+ */
+
+#pragma once
+
+#include <stm32f3.h>
+
+// threshold in ms for press/hold
+#define PRESSTHRESHOLD  (9)
+#define HOLDTHRESHOLD   (199)
+
+// events
+typedef enum{
+    EVT_NONE,   // no events with given key
+    EVT_PRESS,  // pressed (hold more than PRESSTHRESHOLD ms)
+    EVT_HOLD,   // hold more than HOLDTHRESHOLD ms
+    EVT_RELEASE // released after press or hold state
+} keyevent;
+
+extern uint32_t lastUnsleep; // last keys activity time
+
+void process_keys();
+keyevent keystate(uint8_t k, uint32_t *T);
+keyevent keyevt(uint8_t k);
+