add F103 PL2303 with ring buffer

F1:F103/PL2303_ringbuffer/ringbuffer.h

@@ -0,0 +1,33 @@
+/*
+ * This file is part of the pl2303 project.
+ * Copyright 2022 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
+#ifndef RINGBUFFER_H__
+#define RINGBUFFER_H__
+
+#include "usbhw.h"
+
+// ring buffer size in bytes
+#define RBSIZE      (512)
+// max reading portion size
+#define BLOCKSIZE   (USB_TXBUFSZ)
+
+int RB_read(char s[BLOCKSIZE]);
+void RB_write(const char *str, int l);
+
+#endif // RINGBUFFER_H__