Add option USB CDC to be used for Serial (starting USB early)

boards.txt

@@ -1,5 +1,6 @@
 menu.UploadSpeed=Upload Speed
 menu.UploadMode=Upload Mode
+menu.SerialMode=Serial Connected To
 menu.CPUFreq=CPU Frequency
 menu.FlashFreq=Flash Frequency
 menu.FlashMode=Flash Mode
@@ -30,6 +31,7 @@ esp32s2.build.core=esp32
 esp32s2.build.variant=esp32s2
 esp32s2.build.board=ESP32S2_DEV
 
+esp32s2.build.serial=0
 esp32s2.build.f_cpu=240000000L
 esp32s2.build.flash_size=4MB
 esp32s2.build.flash_freq=80m
@@ -38,6 +40,11 @@ esp32s2.build.boot=qio
 esp32s2.build.partitions=default
 esp32s2.build.defines=
 
+esp32s2.menu.SerialMode.default=UART0
+esp32s2.menu.SerialMode.default.build.serial=0
+esp32s2.menu.SerialMode.cdc=USB CDC
+esp32s2.menu.SerialMode.cdc.build.serial=1
+
 esp32s2.menu.UploadMode.default=Default Uart
 esp32s2.menu.UploadMode.default.upload.flags=
 esp32s2.menu.UploadMode.default.upload.tool=esptool_py

cores/esp32/HardwareSerial.cpp

@@ -37,7 +37,11 @@
 #endif
 
 #if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SERIAL)
+#if ARDUINO_SERIAL_PORT //Serial used for USB CDC
+HardwareSerial Serial0(0);
+#else
 HardwareSerial Serial(0);
+#endif
 HardwareSerial Serial1(1);
 #if CONFIG_IDF_TARGET_ESP32
 HardwareSerial Serial2(2);

cores/esp32/HardwareSerial.h

@@ -113,8 +113,13 @@ protected:
 extern void serialEventRun(void) __attribute__((weak));
 
 #if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SERIAL)
+#if ARDUINO_SERIAL_PORT //Serial used for USB CDC
+#include "USB.h"
+#include "USBCDC.h"
+extern HardwareSerial Serial0;
+#else
 extern HardwareSerial Serial;
-extern HardwareSerial Serial1;
+#endif
 #if CONFIG_IDF_TARGET_ESP32
 extern HardwareSerial Serial2;
 #endif

cores/esp32/USBCDC.cpp

@@ -329,6 +329,10 @@ USBCDC::operator bool() const
     return connected;
 }
 
+#if ARDUINO_SERIAL_PORT //Serial used for USB CDC
+USBCDC Serial(0);
+#endif
+
 #endif /* CONFIG_USB_CDC_ENABLED */
 
 #endif /* CONFIG_USB_ENABLED */

cores/esp32/USBCDC.h

@@ -126,6 +126,8 @@ protected:
     
 };
 
-extern void serialEventRun(void) __attribute__((weak));
+#if ARDUINO_SERIAL_PORT //Serial used for USB CDC
+extern USBCDC Serial;
+#endif
 
 #endif /* CONFIG_USB_CDC_ENABLED */

cores/esp32/main.cpp

@@ -2,6 +2,9 @@
 #include "freertos/task.h"
 #include "esp_task_wdt.h"
 #include "Arduino.h"
+#if ARDUINO_SERIAL_PORT //Serial used for USB CDC
+#include "USB.h"
+#endif
 
 TaskHandle_t loopTaskHandle = NULL;
 
@@ -36,6 +39,9 @@ void loopTask(void *pvParameters)
 
 extern "C" void app_main()
 {
+#if ARDUINO_SERIAL_PORT //Serial used for USB CDC
+    USB.begin();
+#endif
     loopTaskWDTEnabled = false;
     initArduino();
     xTaskCreateUniversal(loopTask, "loopTask", 8192, NULL, 1, &loopTaskHandle, CONFIG_ARDUINO_RUNNING_CORE);

platform.txt

@@ -29,6 +29,7 @@ compiler.cpp.flags.esp32=-mlongcalls -Wno-frame-address -ffunction-sections -fda
 compiler.S.flags.esp32=-ffunction-sections -fdata-sections -fstrict-volatile-bitfields -Wno-error=unused-function -Wno-error=unused-but-set-variable -Wno-error=unused-variable -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-sign-compare -ggdb -mfix-esp32-psram-cache-issue -mfix-esp32-psram-cache-strategy=memw -Og -fstack-protector  -x assembler-with-cpp -MMD -c
 compiler.c.elf.flags.esp32=-mlongcalls -T esp32.rom.ld -T esp32.rom.libgcc.ld -T esp32.rom.newlib-data.ld -T esp32.rom.syscalls.ld -T esp32_out.ld -T esp32.project.ld -T esp32.peripherals.ld  -Wl,--cref -fno-rtti -fno-lto -u esp_app_desc -u vfs_include_syscalls_impl -u pthread_include_pthread_impl -u pthread_include_pthread_cond_impl -u pthread_include_pthread_local_storage_impl -u app_main -u call_user_start_cpu0 -u ld_include_panic_highint_hdl -mfix-esp32-psram-cache-issue -mfix-esp32-psram-cache-strategy=memw -Wl,--gc-sections -Wl,--undefined=uxTopUsedPriority -u newlib_include_locks_impl -u newlib_include_heap_impl -u newlib_include_syscalls_impl -u newlib_include_pthread_impl -u __cxa_guard_dummy 
 compiler.ar.flags.esp32=cru
+build.extra_flags.esp32=-DARDUINO_SERIAL_PORT=0
 #
 # ESP32 Support End
 #
@@ -43,6 +44,7 @@ compiler.cpp.flags.esp32s2=-mlongcalls -ffunction-sections -fdata-sections -fstr
 compiler.S.flags.esp32s2=-ffunction-sections -fdata-sections -fstrict-volatile-bitfields -Wno-error=unused-function -Wno-error=unused-but-set-variable -Wno-error=unused-variable -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-sign-compare -ggdb -Og -fstack-protector  -x assembler-with-cpp -MMD -c
 compiler.c.elf.flags.esp32s2=-mlongcalls -T esp32s2.rom.ld -T esp32s2.rom.libgcc.ld -T esp32s2.rom.newlib-data.ld -T esp32s2.rom.newlib-funcs.ld -T esp32s2.rom.spiflash.ld -T esp32s2_out.ld -T esp32s2.project.ld -T esp32s2.peripherals.ld  -Wl,--cref -fno-rtti -fno-lto -u esp_app_desc -u vfs_include_syscalls_impl -u pthread_include_pthread_impl -u pthread_include_pthread_cond_impl -u pthread_include_pthread_local_storage_impl -u app_main -u call_user_start_cpu0 -u ld_include_panic_highint_hdl -Wl,--gc-sections -Wl,--undefined=uxTopUsedPriority -u newlib_include_locks_impl -u newlib_include_heap_impl -u newlib_include_syscalls_impl -u newlib_include_pthread_impl -u __cxa_guard_dummy 
 compiler.ar.flags.esp32s2=cru
+build.extra_flags.esp32s2=-DARDUINO_SERIAL_PORT={build.serial}
 #
 # ESP32S2 Support End
 #
@@ -88,7 +90,7 @@ build.flash_mode=dio
 build.boot=bootloader
 build.code_debug=0
 build.defines=
-build.extra_flags=-DESP32 -DCORE_DEBUG_LEVEL={build.code_debug} {build.defines}
+build.extra_flags=-DESP32 -DCORE_DEBUG_LEVEL={build.code_debug} {build.defines} {build.extra_flags.{build.mcu}}
 
 # Check if custom partitions exist
 recipe.hooks.prebuild.1.pattern=bash -c "[ ! -f {build.source.path}/partitions.csv ] || cp -f {build.source.path}/partitions.csv {build.path}/partitions.csv"