USB CDC on STM32G0B1 works

snippets/USB_CDC_ringbuffer/dbg.h

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+/*
+ * This file is part of the test project.
+ * Copyright 2026 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
+
+// debugging messages on config interface
+#ifdef EBUG
+#include "usart.h"
+#include "strfunc.h"
+
+#define STR_HELPER(s)   #s
+#define STR(s)          STR_HELPER(s)
+#define DBGl(str)       do{usart_sendstr(__FILE__ " (L" STR(__LINE__) "): " str); usart_send("\n", 1);}while(0)
+#define DBGs(str)       usart_sendstr(str)
+#define DBGch(ch)       usart_send(ch, 1)
+#define DBGn()          usart_send("\n", 1)
+#else
+#define DBGl(str)
+#define DBGs(str)
+#define DBGch(ch)
+#define DBGn()
+#define DBGpri()
+#endif