seems like it works, the rest is only CDC and composite; and then test on 072 and 303

F1:F103/USB_New_concept/USB_NEW_concept_PL2303/main.c

@@ -0,0 +1,71 @@
+/*
+ * This file is part of the I2Cscan project.
+ * Copyright 2020 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/>.
+ */
+
+#include "hardware.h"
+#ifdef EBUG
+#include "usart.h"
+#endif
+#include "usb_dev.h"
+
+volatile uint32_t Tms = 0;
+
+/* Called when systick fires */
+void sys_tick_handler(void){
+    ++Tms;
+}
+
+#define STRLEN  (256)
+
+int main(void){
+    char inbuff[RBINSZ];
+    uint32_t lastT = 0;
+    StartHSE();
+    hw_setup();
+    USBPU_OFF();
+    SysTick_Config(72000);
+#ifdef EBUG
+    usart_setup();
+    uint32_t tt = 0;
+#endif
+    USB_setup();
+#ifndef EBUG
+    iwdg_setup();
+#endif
+    USBPU_ON();
+    while (1){
+        IWDG->KR = IWDG_REFRESH; // refresh watchdog
+        if(Tms - lastT > 499){
+            LED_blink(LED0);
+            lastT = Tms;
+        }
+#ifdef EBUG
+        if(Tms != tt){
+            __disable_irq();
+            usart_transmit();
+            tt = Tms;
+            __enable_irq();
+        }
+#endif
+        int l = USB_receivestr(inbuff, RBINSZ);
+        if(l < 0) USB_sendstr("ERROR: USB buffer overflow or string was too long\n");
+        else if(l){
+            USB_sendstr("RECEIVED: _"); USB_sendstr(inbuff); USB_sendstr("_\n");
+        }
+    }
+    return 0;
+}