diff --git a/src/machine/machine_atsamd21_usb.go b/src/machine/machine_atsamd21_usb.go
index 7ddbd590b1..b68046d484 100644
--- a/src/machine/machine_atsamd21_usb.go
+++ b/src/machine/machine_atsamd21_usb.go
@@ -334,6 +334,8 @@ func SendUSBInPacket(ep uint32, data []byte) bool {
 	return true
 }
 
+// Prevent file size increases: https://github.com/tinygo-org/tinygo/pull/998
+//
 //go:noinline
 func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
 	l := uint16(len(data))
diff --git a/src/machine/machine_atsamd51_usb.go b/src/machine/machine_atsamd51_usb.go
index 426c4b53d6..f33f68a938 100644
--- a/src/machine/machine_atsamd51_usb.go
+++ b/src/machine/machine_atsamd51_usb.go
@@ -337,6 +337,8 @@ func SendUSBInPacket(ep uint32, data []byte) bool {
 	return true
 }
 
+// Prevent file size increases: https://github.com/tinygo-org/tinygo/pull/998
+//
 //go:noinline
 func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
 	l := uint16(len(data))
diff --git a/src/machine/machine_nrf52840_usb.go b/src/machine/machine_nrf52840_usb.go
index 3dde466367..46d6a66e5f 100644
--- a/src/machine/machine_nrf52840_usb.go
+++ b/src/machine/machine_nrf52840_usb.go
@@ -252,6 +252,8 @@ func SendUSBInPacket(ep uint32, data []byte) bool {
 	return true
 }
 
+// Prevent file size increases: https://github.com/tinygo-org/tinygo/pull/998
+//
 //go:noinline
 func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
 	count := len(data)
diff --git a/src/machine/machine_rp2040_usb.go b/src/machine/machine_rp2040_usb.go
index d69cd6ad5f..627afd808f 100644
--- a/src/machine/machine_rp2040_usb.go
+++ b/src/machine/machine_rp2040_usb.go
@@ -6,16 +6,6 @@ import (
 	"device/rp"
 	"machine/usb"
 	"runtime/interrupt"
-	"runtime/volatile"
-	"unsafe"
-)
-
-var (
-	sendOnEP0DATADONE struct {
-		offset int
-		data   []byte
-		pid    uint32
-	}
 )
 
 // Configure the USB peripheral. The config is here for compatibility with the UART interface.
@@ -134,40 +124,6 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 	}
 }
 
-func initEndpoint(ep, config uint32) {
-	val := uint32(usbEpControlEnable) | uint32(usbEpControlInterruptPerBuff)
-	offset := ep*2*usbBufferLen + 0x100
-	val |= offset
-
-	switch config {
-	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointIn:
-		val |= usbEpControlEndpointTypeInterrupt
-		_usbDPSRAM.EPxControl[ep].In.Set(val)
-
-	case usb.ENDPOINT_TYPE_BULK | usb.EndpointOut:
-		val |= usbEpControlEndpointTypeBulk
-		_usbDPSRAM.EPxControl[ep].Out.Set(val)
-		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointOut:
-		val |= usbEpControlEndpointTypeInterrupt
-		_usbDPSRAM.EPxControl[ep].Out.Set(val)
-		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	case usb.ENDPOINT_TYPE_BULK | usb.EndpointIn:
-		val |= usbEpControlEndpointTypeBulk
-		_usbDPSRAM.EPxControl[ep].In.Set(val)
-
-	case usb.ENDPOINT_TYPE_CONTROL:
-		val |= usbEpControlEndpointTypeControl
-		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBuf0CtrlData1Pid)
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	}
-}
-
 func handleUSBSetAddress(setup usb.Setup) bool {
 	// Using 570μs timeout which is exactly the same as SAMD21.
 	const ackTimeout = 570
@@ -188,191 +144,6 @@ func handleUSBSetAddress(setup usb.Setup) bool {
 	return true
 }
 
-// SendUSBInPacket sends a packet for USB (interrupt in / bulk in).
-func SendUSBInPacket(ep uint32, data []byte) bool {
-	sendUSBPacket(ep, data, 0)
-	return true
-}
-
-//go:noinline
-func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
-	count := len(data)
-	if 0 < int(maxsize) && int(maxsize) < count {
-		count = int(maxsize)
-	}
-
-	if ep == 0 {
-		if count > usb.EndpointPacketSize {
-			count = usb.EndpointPacketSize
-
-			sendOnEP0DATADONE.offset = count
-			sendOnEP0DATADONE.data = data
-		} else {
-			sendOnEP0DATADONE.offset = 0
-		}
-		epXdata0[ep] = true
-	}
-
-	sendViaEPIn(ep, data, count)
-}
-
-func ReceiveUSBControlPacket() ([cdcLineInfoSize]byte, error) {
-	var b [cdcLineInfoSize]byte
-	ep := 0
-
-	for !_usbDPSRAM.EPxBufferControl[ep].Out.HasBits(usbBuf0CtrlFull) {
-		// TODO: timeout
-	}
-
-	ctrl := _usbDPSRAM.EPxBufferControl[ep].Out.Get()
-	_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-	sz := ctrl & usbBuf0CtrlLenMask
-
-	copy(b[:], _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz])
-
-	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
-	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	return b, nil
-}
-
-func handleEndpointRx(ep uint32) []byte {
-	ctrl := _usbDPSRAM.EPxBufferControl[ep].Out.Get()
-	_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-	sz := ctrl & usbBuf0CtrlLenMask
-
-	return _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz]
-}
-
-func handleEndpointRxComplete(ep uint32) {
-	epXdata0[ep] = !epXdata0[ep]
-	if epXdata0[ep] || ep == 0 {
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
-	}
-
-	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+func armEPZeroStall() {
+	rp.USBCTRL_REGS.EP_STALL_ARM.Set(rp.USBCTRL_REGS_EP_STALL_ARM_EP0_IN)
 }
-
-func SendZlp() {
-	sendUSBPacket(0, []byte{}, 0)
-}
-
-func sendViaEPIn(ep uint32, data []byte, count int) {
-	// Prepare buffer control register value
-	val := uint32(count) | usbBuf0CtrlAvail
-
-	// DATA0 or DATA1
-	epXdata0[ep&0x7F] = !epXdata0[ep&0x7F]
-	if !epXdata0[ep&0x7F] {
-		val |= usbBuf0CtrlData1Pid
-	}
-
-	// Mark as full
-	val |= usbBuf0CtrlFull
-
-	copy(_usbDPSRAM.EPxBuffer[ep&0x7F].Buffer0[:], data[:count])
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
-}
-
-func sendStallViaEPIn(ep uint32) {
-	// Prepare buffer control register value
-	if ep == 0 {
-		rp.USBCTRL_REGS.EP_STALL_ARM.Set(rp.USBCTRL_REGS_EP_STALL_ARM_EP0_IN)
-	}
-	val := uint32(usbBuf0CtrlFull)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
-	val |= uint32(usbBuf0CtrlStall)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
-}
-
-type usbDPSRAM struct {
-	// Note that EPxControl[0] is not EP0Control but 8-byte setup data.
-	EPxControl [16]usbEndpointControlRegister
-
-	EPxBufferControl [16]usbBufferControlRegister
-
-	EPxBuffer [16]usbBuffer
-}
-
-type usbEndpointControlRegister struct {
-	In  volatile.Register32
-	Out volatile.Register32
-}
-type usbBufferControlRegister struct {
-	In  volatile.Register32
-	Out volatile.Register32
-}
-
-type usbBuffer struct {
-	Buffer0 [usbBufferLen]byte
-	Buffer1 [usbBufferLen]byte
-}
-
-var (
-	_usbDPSRAM = (*usbDPSRAM)(unsafe.Pointer(uintptr(0x50100000)))
-	epXdata0   [16]bool
-	setupBytes [8]byte
-)
-
-func (d *usbDPSRAM) setupBytes() []byte {
-
-	data := d.EPxControl[usb.CONTROL_ENDPOINT].In.Get()
-	setupBytes[0] = byte(data)
-	setupBytes[1] = byte(data >> 8)
-	setupBytes[2] = byte(data >> 16)
-	setupBytes[3] = byte(data >> 24)
-
-	data = d.EPxControl[usb.CONTROL_ENDPOINT].Out.Get()
-	setupBytes[4] = byte(data)
-	setupBytes[5] = byte(data >> 8)
-	setupBytes[6] = byte(data >> 16)
-	setupBytes[7] = byte(data >> 24)
-
-	return setupBytes[:]
-}
-
-func (d *usbDPSRAM) clear() {
-	for i := 0; i < len(d.EPxControl); i++ {
-		d.EPxControl[i].In.Set(0)
-		d.EPxControl[i].Out.Set(0)
-		d.EPxBufferControl[i].In.Set(0)
-		d.EPxBufferControl[i].Out.Set(0)
-	}
-}
-
-const (
-	// DPRAM : Endpoint control register
-	usbEpControlEnable                 = 0x80000000
-	usbEpControlDoubleBuffered         = 0x40000000
-	usbEpControlInterruptPerBuff       = 0x20000000
-	usbEpControlInterruptPerDoubleBuff = 0x10000000
-	usbEpControlEndpointType           = 0x0c000000
-	usbEpControlInterruptOnStall       = 0x00020000
-	usbEpControlInterruptOnNak         = 0x00010000
-	usbEpControlBufferAddress          = 0x0000ffff
-
-	usbEpControlEndpointTypeControl   = 0x00000000
-	usbEpControlEndpointTypeISO       = 0x04000000
-	usbEpControlEndpointTypeBulk      = 0x08000000
-	usbEpControlEndpointTypeInterrupt = 0x0c000000
-
-	// Endpoint buffer control bits
-	usbBuf1CtrlFull     = 0x80000000
-	usbBuf1CtrlLast     = 0x40000000
-	usbBuf1CtrlData0Pid = 0x20000000
-	usbBuf1CtrlData1Pid = 0x00000000
-	usbBuf1CtrlSel      = 0x10000000
-	usbBuf1CtrlStall    = 0x08000000
-	usbBuf1CtrlAvail    = 0x04000000
-	usbBuf1CtrlLenMask  = 0x03FF0000
-	usbBuf0CtrlFull     = 0x00008000
-	usbBuf0CtrlLast     = 0x00004000
-	usbBuf0CtrlData0Pid = 0x00000000
-	usbBuf0CtrlData1Pid = 0x00002000
-	usbBuf0CtrlSel      = 0x00001000
-	usbBuf0CtrlStall    = 0x00000800
-	usbBuf0CtrlAvail    = 0x00000400
-	usbBuf0CtrlLenMask  = 0x000003FF
-
-	usbBufferLen = 64
-)
diff --git a/src/machine/machine_rp2350_usb.go b/src/machine/machine_rp2350_usb.go
index b42ce09cca..5a298b1afd 100644
--- a/src/machine/machine_rp2350_usb.go
+++ b/src/machine/machine_rp2350_usb.go
@@ -6,16 +6,6 @@ import (
 	"device/rp"
 	"machine/usb"
 	"runtime/interrupt"
-	"runtime/volatile"
-	"unsafe"
-)
-
-var (
-	sendOnEP0DATADONE struct {
-		offset int
-		data   []byte
-		pid    uint32
-	}
 )
 
 // Configure the USB peripheral. The config is here for compatibility with the UART interface.
@@ -104,7 +94,7 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 
 		s2 := rp.USB.BUFF_STATUS.Get()
 
-		// OUT (PC -> rp2040)
+		// OUT (PC -> rp2350)
 		for i := 0; i < 16; i++ {
 			if s2&(1<<(i*2+1)) > 0 {
 				buf := handleEndpointRx(uint32(i))
@@ -115,7 +105,7 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 			}
 		}
 
-		// IN (rp2040 -> PC)
+		// IN (rp2350 -> PC)
 		for i := 0; i < 16; i++ {
 			if s2&(1<<(i*2)) > 0 {
 				if usbTxHandler[i] != nil {
@@ -137,44 +127,10 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 	}
 }
 
-func initEndpoint(ep, config uint32) {
-	val := uint32(usbEpControlEnable) | uint32(usbEpControlInterruptPerBuff)
-	offset := ep*2*usbBufferLen + 0x100
-	val |= offset
-
-	switch config {
-	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointIn:
-		val |= usbEpControlEndpointTypeInterrupt
-		_usbDPSRAM.EPxControl[ep].In.Set(val)
-
-	case usb.ENDPOINT_TYPE_BULK | usb.EndpointOut:
-		val |= usbEpControlEndpointTypeBulk
-		_usbDPSRAM.EPxControl[ep].Out.Set(val)
-		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointOut:
-		val |= usbEpControlEndpointTypeInterrupt
-		_usbDPSRAM.EPxControl[ep].Out.Set(val)
-		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	case usb.ENDPOINT_TYPE_BULK | usb.EndpointIn:
-		val |= usbEpControlEndpointTypeBulk
-		_usbDPSRAM.EPxControl[ep].In.Set(val)
-
-	case usb.ENDPOINT_TYPE_CONTROL:
-		val |= usbEpControlEndpointTypeControl
-		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBuf0CtrlData1Pid)
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	}
-}
-
 func handleUSBSetAddress(setup usb.Setup) bool {
 	// Using 570μs timeout which is exactly the same as SAMD21.
-
 	const ackTimeout = 570
+
 	rp.USB.SIE_STATUS.Set(rp.USB_SIE_STATUS_ACK_REC)
 	sendUSBPacket(0, []byte{}, 0)
 
@@ -191,191 +147,6 @@ func handleUSBSetAddress(setup usb.Setup) bool {
 	return true
 }
 
-// SendUSBInPacket sends a packet for USB (interrupt in / bulk in).
-func SendUSBInPacket(ep uint32, data []byte) bool {
-	sendUSBPacket(ep, data, 0)
-	return true
-}
-
-//go:noinline
-func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
-	count := len(data)
-	if 0 < int(maxsize) && int(maxsize) < count {
-		count = int(maxsize)
-	}
-
-	if ep == 0 {
-		if count > usb.EndpointPacketSize {
-			count = usb.EndpointPacketSize
-
-			sendOnEP0DATADONE.offset = count
-			sendOnEP0DATADONE.data = data
-		} else {
-			sendOnEP0DATADONE.offset = 0
-		}
-		epXdata0[ep] = true
-	}
-
-	sendViaEPIn(ep, data, count)
-}
-
-func ReceiveUSBControlPacket() ([cdcLineInfoSize]byte, error) {
-	var b [cdcLineInfoSize]byte
-	ep := 0
-
-	for !_usbDPSRAM.EPxBufferControl[ep].Out.HasBits(usbBuf0CtrlFull) {
-		// TODO: timeout
-	}
-
-	ctrl := _usbDPSRAM.EPxBufferControl[ep].Out.Get()
-	_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-	sz := ctrl & usbBuf0CtrlLenMask
-
-	copy(b[:], _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz])
-
-	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
-	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-
-	return b, nil
+func armEPZeroStall() {
+	rp.USB.EP_STALL_ARM.Set(rp.USB_EP_STALL_ARM_EP0_IN)
 }
-
-func handleEndpointRx(ep uint32) []byte {
-	ctrl := _usbDPSRAM.EPxBufferControl[ep].Out.Get()
-	_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
-	sz := ctrl & usbBuf0CtrlLenMask
-
-	return _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz]
-}
-
-func handleEndpointRxComplete(ep uint32) {
-	epXdata0[ep] = !epXdata0[ep]
-	if epXdata0[ep] || ep == 0 {
-		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
-	}
-
-	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
-}
-
-func SendZlp() {
-	sendUSBPacket(0, []byte{}, 0)
-}
-
-func sendViaEPIn(ep uint32, data []byte, count int) {
-	// Prepare buffer control register value
-	val := uint32(count) | usbBuf0CtrlAvail
-
-	// DATA0 or DATA1
-	epXdata0[ep&0x7F] = !epXdata0[ep&0x7F]
-	if !epXdata0[ep&0x7F] {
-		val |= usbBuf0CtrlData1Pid
-	}
-
-	// Mark as full
-	val |= usbBuf0CtrlFull
-
-	copy(_usbDPSRAM.EPxBuffer[ep&0x7F].Buffer0[:], data[:count])
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
-}
-
-func sendStallViaEPIn(ep uint32) {
-	// Prepare buffer control register value
-	if ep == 0 {
-		rp.USB.EP_STALL_ARM.Set(rp.USB_EP_STALL_ARM_EP0_IN)
-	}
-	val := uint32(usbBuf0CtrlFull)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
-	val |= uint32(usbBuf0CtrlStall)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
-}
-
-type usbDPSRAM struct {
-	// Note that EPxControl[0] is not EP0Control but 8-byte setup data.
-	EPxControl [16]usbEndpointControlRegister
-
-	EPxBufferControl [16]usbBufferControlRegister
-
-	EPxBuffer [16]usbBuffer
-}
-
-type usbEndpointControlRegister struct {
-	In  volatile.Register32
-	Out volatile.Register32
-}
-type usbBufferControlRegister struct {
-	In  volatile.Register32
-	Out volatile.Register32
-}
-
-type usbBuffer struct {
-	Buffer0 [usbBufferLen]byte
-	Buffer1 [usbBufferLen]byte
-}
-
-var (
-	_usbDPSRAM = (*usbDPSRAM)(unsafe.Pointer(uintptr(0x50100000)))
-	epXdata0   [16]bool
-	setupBytes [8]byte
-)
-
-func (d *usbDPSRAM) setupBytes() []byte {
-
-	data := d.EPxControl[usb.CONTROL_ENDPOINT].In.Get()
-	setupBytes[0] = byte(data)
-	setupBytes[1] = byte(data >> 8)
-	setupBytes[2] = byte(data >> 16)
-	setupBytes[3] = byte(data >> 24)
-
-	data = d.EPxControl[usb.CONTROL_ENDPOINT].Out.Get()
-	setupBytes[4] = byte(data)
-	setupBytes[5] = byte(data >> 8)
-	setupBytes[6] = byte(data >> 16)
-	setupBytes[7] = byte(data >> 24)
-
-	return setupBytes[:]
-}
-
-func (d *usbDPSRAM) clear() {
-	for i := 0; i < len(d.EPxControl); i++ {
-		d.EPxControl[i].In.Set(0)
-		d.EPxControl[i].Out.Set(0)
-		d.EPxBufferControl[i].In.Set(0)
-		d.EPxBufferControl[i].Out.Set(0)
-	}
-}
-
-const (
-	// DPRAM : Endpoint control register
-	usbEpControlEnable                 = 0x80000000
-	usbEpControlDoubleBuffered         = 0x40000000
-	usbEpControlInterruptPerBuff       = 0x20000000
-	usbEpControlInterruptPerDoubleBuff = 0x10000000
-	usbEpControlEndpointType           = 0x0c000000
-	usbEpControlInterruptOnStall       = 0x00020000
-	usbEpControlInterruptOnNak         = 0x00010000
-	usbEpControlBufferAddress          = 0x0000ffff
-
-	usbEpControlEndpointTypeControl   = 0x00000000
-	usbEpControlEndpointTypeISO       = 0x04000000
-	usbEpControlEndpointTypeBulk      = 0x08000000
-	usbEpControlEndpointTypeInterrupt = 0x0c000000
-
-	// Endpoint buffer control bits
-	usbBuf1CtrlFull     = 0x80000000
-	usbBuf1CtrlLast     = 0x40000000
-	usbBuf1CtrlData0Pid = 0x20000000
-	usbBuf1CtrlData1Pid = 0x00000000
-	usbBuf1CtrlSel      = 0x10000000
-	usbBuf1CtrlStall    = 0x08000000
-	usbBuf1CtrlAvail    = 0x04000000
-	usbBuf1CtrlLenMask  = 0x03FF0000
-	usbBuf0CtrlFull     = 0x00008000
-	usbBuf0CtrlLast     = 0x00004000
-	usbBuf0CtrlData0Pid = 0x00000000
-	usbBuf0CtrlData1Pid = 0x00002000
-	usbBuf0CtrlSel      = 0x00001000
-	usbBuf0CtrlStall    = 0x00000800
-	usbBuf0CtrlAvail    = 0x00000400
-	usbBuf0CtrlLenMask  = 0x000003FF
-
-	usbBufferLen = 64
-)
diff --git a/src/machine/machine_rp2_usb.go b/src/machine/machine_rp2_usb.go
new file mode 100644
index 0000000000..414fedb5b6
--- /dev/null
+++ b/src/machine/machine_rp2_usb.go
@@ -0,0 +1,242 @@
+//go:build rp2040 || rp2350
+
+package machine
+
+import (
+	"machine/usb"
+	"runtime/volatile"
+	"unsafe"
+)
+
+var (
+	sendOnEP0DATADONE struct {
+		offset int
+		data   []byte
+		pid    uint32
+	}
+)
+
+func initEndpoint(ep, config uint32) {
+	val := uint32(usbEpControlEnable) | uint32(usbEpControlInterruptPerBuff)
+	offset := ep*2*usbBufferLen + 0x100
+	val |= offset
+
+	switch config {
+	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointIn:
+		val |= usbEpControlEndpointTypeInterrupt
+		_usbDPSRAM.EPxControl[ep].In.Set(val)
+
+	case usb.ENDPOINT_TYPE_BULK | usb.EndpointOut:
+		val |= usbEpControlEndpointTypeBulk
+		_usbDPSRAM.EPxControl[ep].Out.Set(val)
+		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
+		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+
+	case usb.ENDPOINT_TYPE_INTERRUPT | usb.EndpointOut:
+		val |= usbEpControlEndpointTypeInterrupt
+		_usbDPSRAM.EPxControl[ep].Out.Set(val)
+		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
+		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+
+	case usb.ENDPOINT_TYPE_BULK | usb.EndpointIn:
+		val |= usbEpControlEndpointTypeBulk
+		_usbDPSRAM.EPxControl[ep].In.Set(val)
+
+	case usb.ENDPOINT_TYPE_CONTROL:
+		val |= usbEpControlEndpointTypeControl
+		_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBuf0CtrlData1Pid)
+		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+
+	}
+}
+
+// SendUSBInPacket sends a packet for USB (interrupt in / bulk in).
+func SendUSBInPacket(ep uint32, data []byte) bool {
+	sendUSBPacket(ep, data, 0)
+	return true
+}
+
+// Prevent file size increases: https://github.com/tinygo-org/tinygo/pull/998
+//
+//go:noinline
+func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
+	count := len(data)
+	if 0 < int(maxsize) && int(maxsize) < count {
+		count = int(maxsize)
+	}
+
+	if ep == 0 {
+		if count > usb.EndpointPacketSize {
+			count = usb.EndpointPacketSize
+
+			sendOnEP0DATADONE.offset = count
+			sendOnEP0DATADONE.data = data
+		} else {
+			sendOnEP0DATADONE.offset = 0
+		}
+		epXdata0[ep] = true
+	}
+
+	sendViaEPIn(ep, data, count)
+}
+
+func ReceiveUSBControlPacket() ([cdcLineInfoSize]byte, error) {
+	var b [cdcLineInfoSize]byte
+	ep := 0
+
+	for !_usbDPSRAM.EPxBufferControl[ep].Out.HasBits(usbBuf0CtrlFull) {
+		// TODO: timeout
+	}
+
+	ctrl := _usbDPSRAM.EPxBufferControl[ep].Out.Get()
+	_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
+	sz := ctrl & usbBuf0CtrlLenMask
+
+	copy(b[:], _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz])
+
+	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
+	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+
+	return b, nil
+}
+
+func handleEndpointRx(ep uint32) []byte {
+	ctrl := _usbDPSRAM.EPxBufferControl[ep].Out.Get()
+	_usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBufferLen & usbBuf0CtrlLenMask)
+	sz := ctrl & usbBuf0CtrlLenMask
+
+	return _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz]
+}
+
+func handleEndpointRxComplete(ep uint32) {
+	epXdata0[ep] = !epXdata0[ep]
+	if epXdata0[ep] || ep == 0 {
+		_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
+	}
+
+	_usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+}
+
+func SendZlp() {
+	sendUSBPacket(0, []byte{}, 0)
+}
+
+func sendViaEPIn(ep uint32, data []byte, count int) {
+	// Prepare buffer control register value
+	val := uint32(count) | usbBuf0CtrlAvail
+
+	// DATA0 or DATA1
+	epXdata0[ep&0x7F] = !epXdata0[ep&0x7F]
+	if !epXdata0[ep&0x7F] {
+		val |= usbBuf0CtrlData1Pid
+	}
+
+	// Mark as full
+	val |= usbBuf0CtrlFull
+
+	copy(_usbDPSRAM.EPxBuffer[ep&0x7F].Buffer0[:], data[:count])
+	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
+}
+
+func sendStallViaEPIn(ep uint32) {
+	// Prepare buffer control register value
+	if ep == 0 {
+		armEPZeroStall()
+	}
+	val := uint32(usbBuf0CtrlFull)
+	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
+	val |= uint32(usbBuf0CtrlStall)
+	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
+}
+
+type usbDPSRAM struct {
+	// Note that EPxControl[0] is not EP0Control but 8-byte setup data.
+	EPxControl [16]usbEndpointControlRegister
+
+	EPxBufferControl [16]usbBufferControlRegister
+
+	EPxBuffer [16]usbBuffer
+}
+
+type usbEndpointControlRegister struct {
+	In  volatile.Register32
+	Out volatile.Register32
+}
+type usbBufferControlRegister struct {
+	In  volatile.Register32
+	Out volatile.Register32
+}
+
+type usbBuffer struct {
+	Buffer0 [usbBufferLen]byte
+	Buffer1 [usbBufferLen]byte
+}
+
+var (
+	_usbDPSRAM = (*usbDPSRAM)(unsafe.Pointer(uintptr(0x50100000)))
+	epXdata0   [16]bool
+	setupBytes [8]byte
+)
+
+func (d *usbDPSRAM) setupBytes() []byte {
+
+	data := d.EPxControl[usb.CONTROL_ENDPOINT].In.Get()
+	setupBytes[0] = byte(data)
+	setupBytes[1] = byte(data >> 8)
+	setupBytes[2] = byte(data >> 16)
+	setupBytes[3] = byte(data >> 24)
+
+	data = d.EPxControl[usb.CONTROL_ENDPOINT].Out.Get()
+	setupBytes[4] = byte(data)
+	setupBytes[5] = byte(data >> 8)
+	setupBytes[6] = byte(data >> 16)
+	setupBytes[7] = byte(data >> 24)
+
+	return setupBytes[:]
+}
+
+func (d *usbDPSRAM) clear() {
+	for i := 0; i < len(d.EPxControl); i++ {
+		d.EPxControl[i].In.Set(0)
+		d.EPxControl[i].Out.Set(0)
+		d.EPxBufferControl[i].In.Set(0)
+		d.EPxBufferControl[i].Out.Set(0)
+	}
+}
+
+const (
+	// DPRAM : Endpoint control register
+	usbEpControlEnable                 = 0x80000000
+	usbEpControlDoubleBuffered         = 0x40000000
+	usbEpControlInterruptPerBuff       = 0x20000000
+	usbEpControlInterruptPerDoubleBuff = 0x10000000
+	usbEpControlEndpointType           = 0x0c000000
+	usbEpControlInterruptOnStall       = 0x00020000
+	usbEpControlInterruptOnNak         = 0x00010000
+	usbEpControlBufferAddress          = 0x0000ffff
+
+	usbEpControlEndpointTypeControl   = 0x00000000
+	usbEpControlEndpointTypeISO       = 0x04000000
+	usbEpControlEndpointTypeBulk      = 0x08000000
+	usbEpControlEndpointTypeInterrupt = 0x0c000000
+
+	// Endpoint buffer control bits
+	usbBuf1CtrlFull     = 0x80000000
+	usbBuf1CtrlLast     = 0x40000000
+	usbBuf1CtrlData0Pid = 0x20000000
+	usbBuf1CtrlData1Pid = 0x00000000
+	usbBuf1CtrlSel      = 0x10000000
+	usbBuf1CtrlStall    = 0x08000000
+	usbBuf1CtrlAvail    = 0x04000000
+	usbBuf1CtrlLenMask  = 0x03FF0000
+	usbBuf0CtrlFull     = 0x00008000
+	usbBuf0CtrlLast     = 0x00004000
+	usbBuf0CtrlData0Pid = 0x00000000
+	usbBuf0CtrlData1Pid = 0x00002000
+	usbBuf0CtrlSel      = 0x00001000
+	usbBuf0CtrlStall    = 0x00000800
+	usbBuf0CtrlAvail    = 0x00000400
+	usbBuf0CtrlLenMask  = 0x000003FF
+
+	usbBufferLen = 64
+)