machine/samd21/arduino-nano33: adds support for Arduino Nano33 IoT along with mapping to NINA-W102 WiFi chip.

Also adds DTR and RTS functions along with timeouts to USBCDC functions to prevent lockups.

Signed-off-by: Ron Evans <ron@hybridgroup.com>

src/machine/board_arduino_nano33.go

@@ -0,0 +1,138 @@
+// +build sam,atsamd21,arduino_nano33
+
+// This contains the pin mappings for the Arduino Nano33 IoT board.
+//
+// For more information, see: https://store.arduino.cc/nano-33-iot
+//
+package machine
+
+import "device/sam"
+
+// GPIO Pins
+const (
+	RX0 Pin = PB23 // UART2 RX
+	TX1 Pin = PB22 // UART2 TX
+
+	D2 Pin = PB10 // PWM available
+	D3 Pin = PB11 // PWM available
+	D4 Pin = PA07
+	D5 Pin = PA05 // PWM available
+	D6 Pin = PA04 // PWM available
+	D7 Pin = PA06
+
+	D8  Pin = PA18
+	D9  Pin = PA20 // PWM available
+	D10 Pin = PA21 // PWM available
+	D11 Pin = PA16 // PWM available
+	D12 Pin = PA19 // PWM available
+
+	D13 Pin = PA17
+)
+
+// Analog pins
+const (
+	A0 Pin = PA02 // ADC/AIN[0]
+	A1 Pin = PB02 // ADC/AIN[10]
+	A2 Pin = PA11 // ADC/AIN[19]
+	A3 Pin = PA10 // ADC/AIN[18]
+	A4 Pin = PB08 // ADC/AIN[2], SCL:  SERCOM2/PAD[1]
+	A5 Pin = PB09 // ADC/AIN[3], SDA:  SERCOM2/PAD[1]
+	A6 Pin = PA09 // ADC/AIN[17]
+	A7 Pin = PB03 // ADC/AIN[11]
+)
+
+const (
+	LED = D13
+)
+
+// NINA-W102 Pins
+
+const (
+	NINA_MOSI   Pin = PA12
+	NINA_MISO   Pin = PA13
+	NINA_CS     Pin = PA14
+	NINA_SCK    Pin = PA15
+	NINA_GPIO0  Pin = PA27
+	NINA_RESETN Pin = PA08
+	NINA_ACK    Pin = PA28
+)
+
+// UART0 aka USBCDC pins
+const (
+	USBCDC_DM_PIN Pin = PA24
+	USBCDC_DP_PIN Pin = PA25
+)
+
+// UART1 on the Arduino Nano 33 connects to the onboard NINA-W102 WiFi chip.
+var (
+	UART1 = UART{Bus: sam.SERCOM5_USART,
+		Buffer: NewRingBuffer(),
+		Mode:   PinSERCOMAlt,
+		IRQVal: sam.IRQ_SERCOM5,
+	}
+)
+
+// UART1 pins
+const (
+	UART_TX_PIN Pin = PA22
+	UART_RX_PIN Pin = PA23
+)
+
+//go:export SERCOM5_IRQHandler
+func handleUART1() {
+	defaultUART1Handler()
+}
+
+// UART2 on the Arduino Nano 33 connects to the normal TX/RX pins.
+var (
+	UART2 = UART{Bus: sam.SERCOM3_USART,
+		Buffer: NewRingBuffer(),
+		Mode:   PinSERCOMAlt,
+		IRQVal: sam.IRQ_SERCOM3,
+	}
+)
+
+//go:export SERCOM3_IRQHandler
+func handleUART2() {
+	// should reset IRQ
+	UART2.Receive(byte((UART2.Bus.DATA.Get() & 0xFF)))
+	UART2.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INTFLAG_RXC)
+}
+
+// I2C pins
+const (
+	SDA_PIN Pin = A4 // SDA: SERCOM4/PAD[1]
+	SCL_PIN Pin = A5 // SCL: SERCOM4/PAD[1]
+)
+
+// I2C on the Arduino Nano 33.
+var (
+	I2C0 = I2C{Bus: sam.SERCOM4_I2CM,
+		SDA:     SDA_PIN,
+		SCL:     SCL_PIN,
+		PinMode: PinSERCOMAlt}
+)
+
+// SPI pins
+const (
+	SPI0_SCK_PIN  Pin = PB11 // SCK: SERCOM4/PAD[3]
+	SPI0_MOSI_PIN Pin = PB10 // MOSI: SERCOM4/PAD[2]
+	SPI0_MISO_PIN Pin = PA12 // MISO: SERCOM4/PAD[0]
+)
+
+// SPI on the Arduino Nano 33.
+var (
+	SPI0 = SPI{Bus: sam.SERCOM1_SPI}
+)
+
+// I2S pins
+const (
+	I2S_SCK_PIN Pin = PA10
+	I2S_SD_PIN  Pin = PA08
+	I2S_WS_PIN      = NoPin // TODO: figure out what this is on Arduino Nano 33.
+)
+
+// I2S on the Arduino Nano 33.
+var (
+	I2S0 = I2S{Bus: sam.I2S}
+)

src/machine/board_circuitplay_express.go

@@ -65,6 +65,20 @@ const (
 	UART_RX_PIN = PB09 // PORTB
 )
 
+// UART1 on the Circuit Playground Express.
+var (
+	UART1 = UART{Bus: sam.SERCOM1_USART,
+		Buffer: NewRingBuffer(),
+		Mode:   PinSERCOM,
+		IRQVal: sam.IRQ_SERCOM1,
+	}
+)
+
+//go:export SERCOM1_IRQHandler
+func handleUART1() {
+	defaultUART1Handler()
+}
+
 // I2C pins
 const (
 	SDA_PIN = PB02 // I2C0 external

src/machine/board_feather-m0.go

@@ -48,6 +48,20 @@ const (
 	UART_RX_PIN = D11
 )
 
+// UART1 on the Feather M0.
+var (
+	UART1 = UART{Bus: sam.SERCOM1_USART,
+		Buffer: NewRingBuffer(),
+		Mode:   PinSERCOM,
+		IRQVal: sam.IRQ_SERCOM1,
+	}
+)
+
+//go:export SERCOM1_IRQHandler
+func handleUART1() {
+	defaultUART1Handler()
+}
+
 // I2C pins
 const (
 	SDA_PIN = PA22 // SDA: SERCOM3/PAD[0]

src/machine/board_itsybitsy-m0.go

@@ -48,6 +48,20 @@ const (
 	UART_RX_PIN = D11
 )
 
+// UART1 on the ItsyBitsy M0.
+var (
+	UART1 = UART{Bus: sam.SERCOM1_USART,
+		Buffer: NewRingBuffer(),
+		Mode:   PinSERCOM,
+		IRQVal: sam.IRQ_SERCOM1,
+	}
+)
+
+//go:export SERCOM1_IRQHandler
+func handleUART1() {
+	defaultUART1Handler()
+}
+
 // I2C pins
 const (
 	SDA_PIN = PA22 // SDA: SERCOM3/PAD[0]

src/machine/board_trinket.go

@@ -39,6 +39,20 @@ const (
 	UART_RX_PIN = D3
 )
 
+// UART1 on the Trinket M0.
+var (
+	UART1 = UART{Bus: sam.SERCOM1_USART,
+		Buffer: NewRingBuffer(),
+		Mode:   PinSERCOM,
+		IRQVal: sam.IRQ_SERCOM1,
+	}
+)
+
+//go:export SERCOM1_IRQHandler
+func handleUART1() {
+	defaultUART1Handler()
+}
+
 // SPI pins
 const (
 	SPI0_SCK_PIN  = D3

src/machine/machine_atsamd21.go

@@ -250,14 +250,13 @@ func waitADCSync() {
 type UART struct {
 	Buffer *RingBuffer
 	Bus    *sam.SERCOM_USART_Type
+	Mode   PinMode
+	IRQVal uint32
 }
 
 var (
 	// UART0 is actually a USB CDC interface.
 	UART0 = USBCDC{Buffer: NewRingBuffer()}
-
-	// The first hardware serial port on the SAMD21. Uses the SERCOM0 interface.
-	UART1 = UART{Bus: sam.SERCOM1_USART, Buffer: NewRingBuffer()}
 )
 
 const (
@@ -300,6 +299,8 @@ func (uart UART) Configure(config UARTConfig) {
 		txpad = sercomTXPad2
 	case PA16:
 		txpad = sercomTXPad0
+	case PA22:
+		txpad = sercomTXPad0
 	default:
 		panic("Invalid TX pin for UART")
 	}
@@ -315,13 +316,15 @@ func (uart UART) Configure(config UARTConfig) {
 		rxpad = sercomRXPad3
 	case PA17:
 		rxpad = sercomRXPad1
+	case PA23:
+		rxpad = sercomRXPad1
 	default:
 		panic("Invalid RX pin for UART")
 	}
 
 	// configure pins
-	config.TX.Configure(PinConfig{Mode: PinSERCOM})
+	config.TX.Configure(PinConfig{Mode: uart.Mode})
-	config.RX.Configure(PinConfig{Mode: PinSERCOM})
+	config.RX.Configure(PinConfig{Mode: uart.Mode})
 
 	// reset SERCOM0
 	uart.Bus.CTRLA.SetBits(sam.SERCOM_USART_CTRLA_SWRST)
@@ -372,13 +375,7 @@ func (uart UART) Configure(config UARTConfig) {
 	uart.Bus.INTENSET.Set(sam.SERCOM_USART_INTENSET_RXC)
 
 	// Enable RX IRQ.
-	if config.TX == PA10 {
+	arm.EnableIRQ(uart.IRQVal)
-		// UART0
-		arm.EnableIRQ(sam.IRQ_SERCOM0)
-	} else {
-		// UART1 which is the normal default, since UART0 is used for USBCDC.
-		arm.EnableIRQ(sam.IRQ_SERCOM1)
-	}
 }
 
 // SetBaudRate sets the communication speed for the UART.
@@ -404,8 +401,8 @@ func (uart UART) WriteByte(c byte) error {
 	return nil
 }
 
-//go:export SERCOM1_IRQHandler
+// defaultUART1Handler handles the UART1 IRQ.
-func handleUART1() {
+func defaultUART1Handler() {
 	// should reset IRQ
 	UART1.Receive(byte((UART1.Bus.DATA.Get() & 0xFF)))
 	UART1.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INTFLAG_RXC)
@@ -1182,23 +1179,35 @@ func (usbcdc USBCDC) WriteByte(c byte) error {
 		usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Mask << usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Pos)
 
 		// set count of bytes to be sent
-		usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.SetBits((1&usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask)<<usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos |
+		usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.SetBits((1 & usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask) << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
-			(epPacketSize(64) << usb_DEVICE_PCKSIZE_SIZE_Pos))
 
-		// ack transfer complete flag
+		// clear transfer complete flag
 		setEPINTFLAG(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_EPINTFLAG_TRCPT1)
 
 		// send data by setting bank ready
 		setEPSTATUSSET(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_EPSTATUSSET_BK1RDY)
 
 		// wait for transfer to complete
+		timeout := 3000
 		for (getEPINTFLAG(usb_CDC_ENDPOINT_IN) & sam.USB_DEVICE_EPINTFLAG_TRCPT1) == 0 {
+			timeout--
+			if timeout == 0 {
+				return errors.New("USBCDC write byte timeout")
+			}
 		}
 	}
 
 	return nil
 }
 
+func (usbcdc USBCDC) DTR() bool {
+	return (usbLineInfo.lineState & usb_CDC_LINESTATE_DTR) > 0
+}
+
+func (usbcdc USBCDC) RTS() bool {
+	return (usbLineInfo.lineState & usb_CDC_LINESTATE_RTS) > 0
+}
+
 const (
 	// these are SAMD21 specific.
 	usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos  = 0
@@ -1346,6 +1355,7 @@ func handleUSB() {
 
 		// Clear the Bank 0 ready flag on Control OUT
 		setEPSTATUSCLR(0, sam.USB_DEVICE_EPSTATUSCLR_BK0RDY)
+		usbEndpointDescriptors[0].DeviceDescBank[0].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
 
 		ok := false
 		if (setup.bmRequestType & usb_REQUEST_TYPE) == usb_REQUEST_STANDARD {
@@ -1375,19 +1385,24 @@ func handleUSB() {
 		}
 	}
 
-	// Now the actual transfer handlers
+	// Now the actual transfer handlers, ignore endpoint number 0 (setup)
-	eptInts := sam.USB_DEVICE.EPINTSMRY.Get() & 0xFE // Remove endpoint number 0 (setup)
 	var i uint32
 	for i = 1; i < uint32(len(endPoints)); i++ {
 		// Check if endpoint has a pending interrupt
-		if eptInts&(1<<i) > 0 {
+		epFlags := getEPINTFLAG(i)
-			// yes, so handle flags
+		if epFlags > 0 {
-			epFlags := getEPINTFLAG(i)
+			switch i {
-			setEPINTFLAG(i, epFlags)
+			case usb_CDC_ENDPOINT_OUT:
-
+				if (epFlags & sam.USB_DEVICE_EPINTFLAG_TRCPT0) > 0 {
-			// Endpoint Transfer Complete Interrupt
+					handleEndpoint(i)
-			if (epFlags & sam.USB_DEVICE_EPINTFLAG_TRCPT0) > 0 {
+				}
-				handleEndpoint(i)
+				setEPINTFLAG(i, epFlags)
+			case usb_CDC_ENDPOINT_IN, usb_CDC_ENDPOINT_ACM:
+				// set bank ready
+				setEPSTATUSCLR(i, sam.USB_DEVICE_EPSTATUSCLR_BK1RDY)
+
+				// ack transfer complete
+				setEPINTFLAG(i, sam.USB_DEVICE_EPINTFLAG_TRCPT1)
 			}
 		}
 	}
@@ -1403,7 +1418,7 @@ func initEndpoint(ep, config uint32) {
 		usbEndpointDescriptors[ep].DeviceDescBank[1].ADDR.Set(uint32(uintptr(unsafe.Pointer(&udd_ep_in_cache_buffer[ep]))))
 
 		// set endpoint type
-		setEPCFG(ep, getEPCFG(ep)|((usb_ENDPOINT_TYPE_INTERRUPT+1)<<sam.USB_DEVICE_EPCFG_EPTYPE1_Pos))
+		setEPCFG(ep, ((usb_ENDPOINT_TYPE_INTERRUPT + 1) << sam.USB_DEVICE_EPCFG_EPTYPE1_Pos))
 
 	case usb_ENDPOINT_TYPE_BULK | usbEndpointOut:
 		// set packet size
@@ -1413,11 +1428,14 @@ func initEndpoint(ep, config uint32) {
 		usbEndpointDescriptors[ep].DeviceDescBank[0].ADDR.Set(uint32(uintptr(unsafe.Pointer(&udd_ep_out_cache_buffer[ep]))))
 
 		// set endpoint type
-		setEPCFG(ep, getEPCFG(ep)|((usb_ENDPOINT_TYPE_BULK+1)<<sam.USB_DEVICE_EPCFG_EPTYPE0_Pos))
+		setEPCFG(ep, ((usb_ENDPOINT_TYPE_BULK + 1) << sam.USB_DEVICE_EPCFG_EPTYPE0_Pos))
 
-		// ack the current transfer
+		// receive interrupts when current transfer complete
 		setEPINTENSET(ep, sam.USB_DEVICE_EPINTENSET_TRCPT0)
 
+		// set byte count to zero, we have not received anything yet
+		usbEndpointDescriptors[ep].DeviceDescBank[0].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
+
 		// ready for next transfer
 		setEPSTATUSCLR(ep, sam.USB_DEVICE_EPSTATUSCLR_BK0RDY)
 
@@ -1432,7 +1450,7 @@ func initEndpoint(ep, config uint32) {
 		usbEndpointDescriptors[ep].DeviceDescBank[1].ADDR.Set(uint32(uintptr(unsafe.Pointer(&udd_ep_in_cache_buffer[ep]))))
 
 		// set endpoint type
-		setEPCFG(ep, getEPCFG(ep)|((usb_ENDPOINT_TYPE_BULK+1)<<sam.USB_DEVICE_EPCFG_EPTYPE1_Pos))
+		setEPCFG(ep, ((usb_ENDPOINT_TYPE_BULK + 1) << sam.USB_DEVICE_EPCFG_EPTYPE1_Pos))
 
 		// NAK on endpoint IN, the bank is not yet filled in.
 		setEPSTATUSCLR(ep, sam.USB_DEVICE_EPSTATUSCLR_BK1RDY)
@@ -1515,7 +1533,12 @@ func handleStandardSetup(setup usbSetup) bool {
 		setEPSTATUSSET(0, sam.USB_DEVICE_EPSTATUSSET_BK1RDY)
 
 		// wait for transfer to complete
+		timeout := 3000
 		for (getEPINTFLAG(0) & sam.USB_DEVICE_EPINTFLAG_TRCPT1) == 0 {
+			timeout--
+			if timeout == 0 {
+				return true
+			}
 		}
 
 		// last, set the device address to that requested by host
@@ -1659,11 +1682,21 @@ func armRecvCtrlOUT(ep uint32) uint32 {
 	setEPSTATUSCLR(ep, sam.USB_DEVICE_EPSTATUSCLR_BK0RDY)
 
 	// Wait until OUT transfer is ready.
+	timeout := 3000
 	for (getEPSTATUS(ep) & sam.USB_DEVICE_EPSTATUS_BK0RDY) == 0 {
+		timeout--
+		if timeout == 0 {
+			return 0
+		}
 	}
 
 	// Wait until OUT transfer is completed.
+	timeout = 3000
 	for (getEPINTFLAG(ep) & sam.USB_DEVICE_EPINTFLAG_TRCPT0) == 0 {
+		timeout--
+		if timeout == 0 {
+			return 0
+		}
 	}
 
 	// return number of bytes received
@@ -1800,9 +1833,14 @@ func handleEndpoint(ep uint32) {
 		UART0.Receive(byte((udd_ep_out_cache_buffer[ep][i] & 0xFF)))
 	}
 
+	// set byte count to zero
+	usbEndpointDescriptors[ep].DeviceDescBank[0].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
+
+	// set multi packet size to 64
+	usbEndpointDescriptors[ep].DeviceDescBank[0].PCKSIZE.SetBits(64 << usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Pos)
+
 	// set ready for next data
 	setEPSTATUSCLR(ep, sam.USB_DEVICE_EPSTATUSCLR_BK0RDY)
-
 }
 
 func sendZlp(ep uint32) {

src/machine/usb.go

@@ -473,6 +473,9 @@ const (
 	usb_CDC_CS_INTERFACE                = 0x24
 	usb_CDC_CS_ENDPOINT                 = 0x25
 	usb_CDC_DATA_INTERFACE_CLASS        = 0x0A
+
+	usb_CDC_LINESTATE_DTR = 0x01
+	usb_CDC_LINESTATE_RTS = 0x02
 )
 
 // usbDeviceDescBank is the USB device endpoint descriptor.

targets/arduino-nano33.json

@@ -0,0 +1,5 @@
+{
+    "inherits": ["atsamd21g18a"],
+    "build-tags": ["sam", "atsamd21g18a", "arduino_nano33"],
+    "flash": "bossac -d -i -e -w -v -R --offset=0x2000 {bin}"
+}