Support Serial boolean check for Serial Monitor with HID serial emulation

teensy3/usb_dev.c

 		}
 #endif
 #ifdef SEREMU_INTERFACE
-		if (setup.word1 == 0x03000921 && setup.word2 == ((4<<16)|SEREMU_INTERFACE)
-		  && buf[0] == 0xA9 && buf[1] == 0x45 && buf[2] == 0xC2 && buf[3] == 0x6B) {
-			usb_reboot_timer = 5;
-			endpoint0_transmit(NULL, 0);
+		if (setup.word1 == 0x03000921 && setup.word2 == ((4<<16)|SEREMU_INTERFACE)) {
+			if (buf[0] == 0xA9 && buf[1] == 0x45 && buf[2] == 0xC2 && buf[3] == 0x6B) {
+				usb_reboot_timer = 5;
+				endpoint0_transmit(NULL, 0);
+			} else {
+				usb_seremu_online = 1;
+			}
 		}
 #endif
 #ifdef AUDIO_INTERFACE

teensy3/usb_dev.h

 #ifdef SEREMU_INTERFACE
 extern volatile uint8_t usb_seremu_transmit_flush_timer;
 extern void usb_seremu_flush_callback(void);
+extern volatile uint8_t usb_seremu_online;
 #endif
 
 #ifdef KEYBOARD_INTERFACE

teensy3/usb_seremu.c

 static usb_packet_t *rx_packet=NULL;
 static usb_packet_t *tx_packet=NULL;
 static volatile uint8_t tx_noautoflush=0;
+volatile uint8_t usb_seremu_online=0;
 
 #define TRANSMIT_FLUSH_TIMEOUT	5   /* in milliseconds */
 

teensy3/usb_seremu.h

 void usb_seremu_flush_callback(void);
 extern volatile uint8_t usb_seremu_transmit_flush_timer;
 extern volatile uint8_t usb_configuration;
+extern volatile uint8_t usb_seremu_online;
 #ifdef __cplusplus
 }
 #endif
         uint8_t numbits(void) { return 8; }
         uint8_t dtr(void) { return 1; }
         uint8_t rts(void) { return 1; }
-        operator bool() { return usb_configuration; }
+        operator bool() { return usb_configuration && usb_seremu_online; }
 };
 extern usb_seremu_class Serial;
 extern void serialEvent(void);

teensy4/usb.c

 	}
 #endif
 #ifdef SEREMU_INTERFACE
-	if (setup.word1 == 0x03000921 && setup.word2 == ((4<<16)|SEREMU_INTERFACE)
-	  && endpoint0_buffer[0] == 0xA9 && endpoint0_buffer[1] == 0x45
-	  && endpoint0_buffer[2] == 0xC2 && endpoint0_buffer[3] == 0x6B) {
-		printf("seremu reboot request\n");
-		usb_start_sof_interrupts(NUM_INTERFACE);
-		usb_reboot_timer = 80; // TODO: 10 if only 12 Mbit/sec
+	if (setup.word1 == 0x03000921 && setup.word2 == ((4<<16)|SEREMU_INTERFACE)) {
+		if (endpoint0_buffer[0] == 0xA9 && endpoint0_buffer[1] == 0x45
+		  && endpoint0_buffer[2] == 0xC2 && endpoint0_buffer[3] == 0x6B) {
+			printf("seremu reboot request\n");
+			usb_start_sof_interrupts(NUM_INTERFACE);
+			usb_reboot_timer = 80; // TODO: 10 if only 12 Mbit/sec
+		} else {
+			// any other feature report means Arduino Serial Monitor is open
+			usb_seremu_online = 1;
+		}
 	}
 #endif
 #ifdef AUDIO_INTERFACE

teensy4/usb_seremu.c

 
 static volatile uint8_t tx_noautoflush=0;
 extern volatile uint8_t usb_high_speed;
+volatile uint8_t usb_seremu_online=0;
 
 // TODO: should be 2 different timeouts, high speed (480) vs full speed (12)
 #define TRANSMIT_FLUSH_TIMEOUT  75   /* in microseconds */

teensy4/usb_seremu.h

 int usb_seremu_write_buffer_free(void);
 void usb_seremu_flush_output(void);
 extern volatile uint8_t usb_configuration;
+extern volatile uint8_t usb_seremu_online;
 #ifdef __cplusplus
 }
 #endif
         uint8_t numbits(void) { return 8; }
         uint8_t dtr(void) { return 1; }
         uint8_t rts(void) { return 1; }
-        operator bool() { return usb_configuration; }
+        operator bool() { return usb_configuration && usb_seremu_online; }
 };
 extern usb_seremu_class Serial;
 extern void serialEvent(void);