#81: restart HWCDC interrupt after 100ms

lib/serial/GwSerial.h

@@ -4,7 +4,8 @@
 #include "GwLog.h"
 #include "GwBuffer.h"
 #include "GwChannelInterface.h"
-#include "hal/usb_serial_jtag_ll.h"
+
+#define USBCDC_RESTART_TIME 100
 class GwSerialStream;
 class GwSerial : public GwChannelInterface{
     protected:
@@ -71,15 +72,24 @@ template<typename T>
         }
 
         #if CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3
+        /**
+         * issue #81
+         * workaround for the HWCDC beeing stuck at some point in time
+         * with availableForWrite == 0 but the ISR being disabled
+         * we simply give a small delay of 100ms for availableForWrite being 0
+         * and afterwards call isConnected that seems to retrigger the ISR
+        */
         int availableForWrite(HWCDC* c){
             int rt=c->availableForWrite();
             if (rt > 0) {
                 lastWritable=millis();
                 return rt;
             }
-            if (usb_serial_jtag_ll_txfifo_writable() == 1){
-                LOG_INFO("USBserial restart");
-                usb_serial_jtag_ll_ena_intr_mask(USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);
+            unsigned long now=millis();
+            if (now > (lastWritable+USBCDC_RESTART_TIME)){
+                lastWritable=now;
+                LOG_ERROR("***Restart USBCDC***");
+                c->isConnected(); //this seems to retrigger the ISR
             }
             return rt;
         }