From bf4d2fef4aa9114884e98afc6a17974c903acbe9 Mon Sep 17 00:00:00 2001
From: Dima Jolkin <dimajolkin@gmail.com>
Date: Tue, 17 Feb 2026 10:44:37 +0200
Subject: [PATCH] esp32s3-usbserial: common usbserial for both esp32c3 &
 esp32s3

---
 src/machine/machine_esp32_usb.go              | 45 ----------------
 src/machine/machine_esp32s3_usb.go            | 41 --------------
 ..._esp32c3_usb.go => machine_esp32xx_usb.go} | 54 ++++++++++++++++++-
 3 files changed, 52 insertions(+), 88 deletions(-)
 delete mode 100644 src/machine/machine_esp32_usb.go
 delete mode 100644 src/machine/machine_esp32s3_usb.go
 rename src/machine/{machine_esp32c3_usb.go => machine_esp32xx_usb.go} (59%)

diff --git a/src/machine/machine_esp32_usb.go b/src/machine/machine_esp32_usb.go
deleted file mode 100644
index 6f40a48fc..000000000
--- a/src/machine/machine_esp32_usb.go
+++ /dev/null
@@ -1,45 +0,0 @@
-//go:build esp32s3 || esp32c3
-
-package machine
-
-import (
-	"device/esp"
-)
-
-type USB_DEVICE struct {
-	Bus *esp.USB_DEVICE_Type
-}
-
-var (
-	_USBCDC = &USB_DEVICE{
-		Bus: esp.USB_DEVICE,
-	}
-
-	USBCDC Serialer = _USBCDC
-)
-
-type Serialer interface {
-	WriteByte(c byte) error
-	Write(data []byte) (n int, err error)
-	Configure(config UARTConfig) error
-	Buffered() int
-	ReadByte() (byte, error)
-	DTR() bool
-	RTS() bool
-}
-
-func (usbdev *USB_DEVICE) Configure(config UARTConfig) error {
-	return nil
-}
-
-func (usbdev *USB_DEVICE) Buffered() int {
-	return int(usbdev.Bus.GetEP1_CONF_SERIAL_OUT_EP_DATA_AVAIL())
-}
-
-func (usbdev *USB_DEVICE) DTR() bool {
-	return false
-}
-
-func (usbdev *USB_DEVICE) RTS() bool {
-	return false
-}
diff --git a/src/machine/machine_esp32s3_usb.go b/src/machine/machine_esp32s3_usb.go
deleted file mode 100644
index c9bfbe7ed..000000000
--- a/src/machine/machine_esp32s3_usb.go
+++ /dev/null
@@ -1,41 +0,0 @@
-//go:build esp32s3
-
-package machine
-
-import "errors"
-
-func initUSB() {
-	USBCDC.Configure(UARTConfig{BaudRate: 115200})
-}
-
-func (usbdev *USB_DEVICE) WriteByte(c byte) error {
-	timeout := 10000
-	for usbdev.Bus.GetEP1_CONF_SERIAL_IN_EP_DATA_FREE() == 0 && timeout > 0 {
-		timeout--
-	}
-	if timeout == 0 {
-		return nil
-	}
-	usbdev.Bus.SetEP1_RDWR_BYTE(uint32(c))
-	usbdev.Bus.SetEP1_CONF_WR_DONE(1)
-	return nil
-}
-
-func (usbdev *USB_DEVICE) Write(data []byte) (n int, err error) {
-	for _, c := range data {
-		err = usbdev.WriteByte(c)
-		if err != nil {
-			return n, err
-		}
-		n++
-	}
-	return n, nil
-}
-
-func (usbdev *USB_DEVICE) ReadByte() (byte, error) {
-	return 0, errors.New("ReadByte not implemented")
-}
-
-func (usbdev *USB_DEVICE) flush() {
-	usbdev.Bus.SetEP1_CONF_WR_DONE(1)
-}
diff --git a/src/machine/machine_esp32c3_usb.go b/src/machine/machine_esp32xx_usb.go
similarity index 59%
rename from src/machine/machine_esp32c3_usb.go
rename to src/machine/machine_esp32xx_usb.go
index 730967312..bdd1281a8 100644
--- a/src/machine/machine_esp32c3_usb.go
+++ b/src/machine/machine_esp32xx_usb.go
@@ -1,8 +1,26 @@
-//go:build esp32c3
+//go:build esp32s3 || esp32c3
 
 package machine
 
-import "errors"
+import (
+	"device/esp"
+	"errors"
+)
+
+// USB Serial/JTAG Controller
+// See esp32-c3_technical_reference_manual_en.pdf
+// pg. 736
+type USB_DEVICE struct {
+	Bus *esp.USB_DEVICE_Type
+}
+
+var (
+	_USBCDC = &USB_DEVICE{
+		Bus: esp.USB_DEVICE,
+	}
+
+	USBCDC Serialer = _USBCDC
+)
 
 var (
 	errUSBWrongSize            = errors.New("USB: invalid write size")
@@ -10,14 +28,30 @@ var (
 	errUSBBufferEmpty          = errors.New("USB: read buffer empty")
 )
 
+type Serialer interface {
+	WriteByte(c byte) error
+	Write(data []byte) (n int, err error)
+	Configure(config UARTConfig) error
+	Buffered() int
+	ReadByte() (byte, error)
+	DTR() bool
+	RTS() bool
+}
+
 func initUSB() {}
 
+func (usbdev *USB_DEVICE) Configure(config UARTConfig) error {
+	return nil
+}
+
 func (usbdev *USB_DEVICE) WriteByte(c byte) error {
 	if usbdev.Bus.GetEP1_CONF_SERIAL_IN_EP_DATA_FREE() == 0 {
 		return errUSBCouldNotWriteAllData
 	}
+
 	usbdev.Bus.SetEP1_RDWR_BYTE(uint32(c))
 	usbdev.flush()
+
 	return nil
 }
 
@@ -25,26 +59,42 @@ func (usbdev *USB_DEVICE) Write(data []byte) (n int, err error) {
 	if len(data) == 0 || len(data) > 64 {
 		return 0, errUSBWrongSize
 	}
+
 	for i, c := range data {
 		if usbdev.Bus.GetEP1_CONF_SERIAL_IN_EP_DATA_FREE() == 0 {
 			if i > 0 {
 				usbdev.flush()
 			}
+
 			return i, errUSBCouldNotWriteAllData
 		}
 		usbdev.Bus.SetEP1_RDWR_BYTE(uint32(c))
 	}
+
 	usbdev.flush()
 	return len(data), nil
 }
 
+func (usbdev *USB_DEVICE) Buffered() int {
+	return int(usbdev.Bus.GetEP1_CONF_SERIAL_OUT_EP_DATA_AVAIL())
+}
+
 func (usbdev *USB_DEVICE) ReadByte() (byte, error) {
 	if usbdev.Bus.GetEP1_CONF_SERIAL_OUT_EP_DATA_AVAIL() != 0 {
 		return byte(usbdev.Bus.GetEP1_RDWR_BYTE()), nil
 	}
+
 	return 0, nil
 }
 
+func (usbdev *USB_DEVICE) DTR() bool {
+	return false
+}
+
+func (usbdev *USB_DEVICE) RTS() bool {
+	return false
+}
+
 func (usbdev *USB_DEVICE) flush() {
 	usbdev.Bus.SetEP1_CONF_WR_DONE(1)
 	for usbdev.Bus.GetEP1_CONF_SERIAL_IN_EP_DATA_FREE() == 0 {