nrf52840-mdk

Constants

const HasLowFrequencyCrystal = true
const (
	LED		Pin	= LED_GREEN
	LED_GREEN	Pin	= 22
	LED_RED		Pin	= 23
	LED_BLUE	Pin	= 24
)

LEDs on the nrf52840-mdk (nRF52840 dev board)

const (
	UART_TX_PIN	Pin	= 20
	UART_RX_PIN	Pin	= 19
)

UART pins

const (
	SDA_PIN	= NoPin
	SCL_PIN	= NoPin
)

I2C pins (unused)

const (
	SPI0_SCK_PIN	= NoPin
	SPI0_SDO_PIN	= NoPin
	SPI0_SDI_PIN	= NoPin
)

SPI pins (unused)

const (
	TWI_FREQ_100KHZ	= 100000
	TWI_FREQ_400KHZ	= 400000
)

TWI_FREQ is the I2C bus speed. Normally either 100 kHz, or 400 kHz for high-speed bus.

const NoPin = Pin(0xff)

NoPin explicitly indicates “not a pin”. Use this pin if you want to leave one of the pins in a peripheral unconfigured (if supported by the hardware).

const (
	PinInput		PinMode	= (nrf.GPIO_PIN_CNF_DIR_Input << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Connect << nrf.GPIO_PIN_CNF_INPUT_Pos)
	PinInputPullup		PinMode	= PinInput | (nrf.GPIO_PIN_CNF_PULL_Pullup << nrf.GPIO_PIN_CNF_PULL_Pos)
	PinInputPulldown	PinMode	= PinInput | (nrf.GPIO_PIN_CNF_PULL_Pulldown << nrf.GPIO_PIN_CNF_PULL_Pos)
	PinOutput		PinMode	= (nrf.GPIO_PIN_CNF_DIR_Output << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Disconnect << nrf.GPIO_PIN_CNF_INPUT_Pos)
)
const (
	PinRising	PinChange	= nrf.GPIOTE_CONFIG_POLARITY_LoToHi
	PinFalling	PinChange	= nrf.GPIOTE_CONFIG_POLARITY_HiToLo
	PinToggle	PinChange	= nrf.GPIOTE_CONFIG_POLARITY_Toggle
)

Pin change interrupt constants for SetInterrupt.

const (
	P0_00	Pin	= 0
	P0_01	Pin	= 1
	P0_02	Pin	= 2
	P0_03	Pin	= 3
	P0_04	Pin	= 4
	P0_05	Pin	= 5
	P0_06	Pin	= 6
	P0_07	Pin	= 7
	P0_08	Pin	= 8
	P0_09	Pin	= 9
	P0_10	Pin	= 10
	P0_11	Pin	= 11
	P0_12	Pin	= 12
	P0_13	Pin	= 13
	P0_14	Pin	= 14
	P0_15	Pin	= 15
	P0_16	Pin	= 16
	P0_17	Pin	= 17
	P0_18	Pin	= 18
	P0_19	Pin	= 19
	P0_20	Pin	= 20
	P0_21	Pin	= 21
	P0_22	Pin	= 22
	P0_23	Pin	= 23
	P0_24	Pin	= 24
	P0_25	Pin	= 25
	P0_26	Pin	= 26
	P0_27	Pin	= 27
	P0_28	Pin	= 28
	P0_29	Pin	= 29
	P0_30	Pin	= 30
	P0_31	Pin	= 31
	P1_00	Pin	= 32
	P1_01	Pin	= 33
	P1_02	Pin	= 34
	P1_03	Pin	= 35
	P1_04	Pin	= 36
	P1_05	Pin	= 37
	P1_06	Pin	= 38
	P1_07	Pin	= 39
	P1_08	Pin	= 40
	P1_09	Pin	= 41
	P1_10	Pin	= 42
	P1_11	Pin	= 43
	P1_12	Pin	= 44
	P1_13	Pin	= 45
	P1_14	Pin	= 46
	P1_15	Pin	= 47
)

Hardware pins

Variables

var (
	UART0 = USB
)

UART0 is the USB device

var (
	ErrInvalidInputPin	= errors.New("machine: invalid input pin")
	ErrInvalidOutputPin	= errors.New("machine: invalid output pin")
	ErrInvalidClockPin	= errors.New("machine: invalid clock pin")
	ErrInvalidDataPin	= errors.New("machine: invalid data pin")
	ErrNoPinChangeChannel	= errors.New("machine: no channel available for pin interrupt")
)
var (
	ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
)
var (
	// NRF_UART0 is the hardware UART on the NRF SoC.
	NRF_UART0 = UART{Buffer: NewRingBuffer()}
)

UART

var (
	I2C0	= I2C{Bus: nrf.TWI0}
	I2C1	= I2C{Bus: nrf.TWI1}
)

There are 2 I2C interfaces on the NRF.

var (
	SPI0	= SPI{Bus: nrf.SPI0}
	SPI1	= SPI{Bus: nrf.SPI1}
)

There are 2 SPI interfaces on the NRF5x.

var (
	USB	= USBCDC{Buffer: NewRingBuffer()}

	usbEndpointDescriptors	[8]usbDeviceDescriptor

	udd_ep_in_cache_buffer	[7][128]uint8
	udd_ep_out_cache_buffer	[7][128]uint8

	sendOnEP0DATADONE	struct {
		ptr	*byte
		count	int
	}
	isEndpointHalt		= false
	isRemoteWakeUpEnabled	= false
	endPoints		= []uint32{usb_ENDPOINT_TYPE_CONTROL,
		(usb_ENDPOINT_TYPE_INTERRUPT | usbEndpointIn),
		(usb_ENDPOINT_TYPE_BULK | usbEndpointOut),
		(usb_ENDPOINT_TYPE_BULK | usbEndpointIn)}

	usbConfiguration		uint8
	usbSetInterface			uint8
	usbLineInfo			= cdcLineInfo{115200, 0x00, 0x00, 0x08, 0x00}
	epinen				uint32
	epouten				uint32
	easyDMABusy			volatile.Register8
	epout0data_setlinecoding	bool
)

func CPUFrequency

func CPUFrequency() uint32

func InitADC

func InitADC()

InitADC initializes the registers needed for ADC.

func InitPWM

func InitPWM()

InitPWM initializes the registers needed for PWM.

func NewACMFunctionalDescriptor

func NewACMFunctionalDescriptor(subtype, d0 uint8) ACMFunctionalDescriptor

NewACMFunctionalDescriptor returns a new USB ACMFunctionalDescriptor.

func NewCDCCSInterfaceDescriptor

func NewCDCCSInterfaceDescriptor(subtype, d0, d1 uint8) CDCCSInterfaceDescriptor

NewCDCCSInterfaceDescriptor returns a new USB CDCCSInterfaceDescriptor.

func NewCDCDescriptor

func NewCDCDescriptor(i IADDescriptor, c InterfaceDescriptor,
	h CDCCSInterfaceDescriptor,
	cm ACMFunctionalDescriptor,
	fd CDCCSInterfaceDescriptor,
	callm CMFunctionalDescriptor,
	ci EndpointDescriptor,
	di InterfaceDescriptor,
	outp EndpointDescriptor,
	inp EndpointDescriptor) CDCDescriptor

func NewCMFunctionalDescriptor

func NewCMFunctionalDescriptor(subtype, d0, d1 uint8) CMFunctionalDescriptor

NewCMFunctionalDescriptor returns a new USB CMFunctionalDescriptor.

func NewConfigDescriptor

func NewConfigDescriptor(totalLength uint16, interfaces uint8) ConfigDescriptor

NewConfigDescriptor returns a new USB ConfigDescriptor.

func NewDeviceDescriptor

func NewDeviceDescriptor(class, subClass, proto, packetSize0 uint8, vid, pid, version uint16, im, ip, is, configs uint8) DeviceDescriptor

NewDeviceDescriptor returns a USB DeviceDescriptor.

func NewEndpointDescriptor

func NewEndpointDescriptor(addr, attr uint8, packetSize uint16, interval uint8) EndpointDescriptor

NewEndpointDescriptor returns a new USB EndpointDescriptor.

func NewIADDescriptor

func NewIADDescriptor(firstInterface, count, class, subClass, protocol uint8) IADDescriptor

NewIADDescriptor returns a new USB IADDescriptor.

func NewInterfaceDescriptor

func NewInterfaceDescriptor(n, numEndpoints, class, subClass, protocol uint8) InterfaceDescriptor

NewInterfaceDescriptor returns a new USB InterfaceDescriptor.

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

type ACMFunctionalDescriptor

type ACMFunctionalDescriptor struct {
	len		uint8
	dtype		uint8	// 0x24
	subtype		uint8	// 1
	bmCapabilities	uint8
}

ACMFunctionalDescriptor is a Abstract Control Model (ACM) USB descriptor.

func (ACMFunctionalDescriptor) Bytes

func (d ACMFunctionalDescriptor) Bytes() []byte

Bytes returns the ACMFunctionalDescriptor data.

type ADC

type ADC struct {
	Pin Pin
}

func (ADC) Configure

func (a ADC) Configure() error

Configure configures an ADC pin to be able to read analog data.

func (ADC) Get

func (a ADC) Get() uint16

Get returns the current value of a ADC pin in the range 0..0xffff.

type CDCCSInterfaceDescriptor

type CDCCSInterfaceDescriptor struct {
	len	uint8	// 5
	dtype	uint8	// 0x24
	subtype	uint8
	d0	uint8
	d1	uint8
}

CDCCSInterfaceDescriptor is a CDC CS interface descriptor.

func (CDCCSInterfaceDescriptor) Bytes

func (d CDCCSInterfaceDescriptor) Bytes() []byte

Bytes returns CDCCSInterfaceDescriptor data.

type CDCDescriptor

type CDCDescriptor struct {
	//	IAD
	iad	IADDescriptor	// Only needed on compound device

	//	Control
	cif	InterfaceDescriptor
	header	CDCCSInterfaceDescriptor

	// CDC control
	controlManagement	ACMFunctionalDescriptor		// ACM
	functionalDescriptor	CDCCSInterfaceDescriptor	// CDC_UNION
	callManagement		CMFunctionalDescriptor		// Call Management
	cifin			EndpointDescriptor

	//	CDC Data
	dif	InterfaceDescriptor
	in	EndpointDescriptor
	out	EndpointDescriptor
}

CDCDescriptor is the Communication Device Class (CDC) descriptor.

func (CDCDescriptor) Bytes

func (d CDCDescriptor) Bytes() []byte

Bytes returns CDCDescriptor data.

type CMFunctionalDescriptor

type CMFunctionalDescriptor struct {
	bFunctionLength		uint8
	bDescriptorType		uint8	// 0x24
	bDescriptorSubtype	uint8	// 1
	bmCapabilities		uint8
	bDataInterface		uint8
}

CMFunctionalDescriptor is the functional descriptor general format.

func (CMFunctionalDescriptor) Bytes

func (d CMFunctionalDescriptor) Bytes() []byte

Bytes returns the CMFunctionalDescriptor data.

type ConfigDescriptor

type ConfigDescriptor struct {
	bLength			uint8	// 9
	bDescriptorType		uint8	// 2
	wTotalLength		uint16	// total length
	bNumInterfaces		uint8
	bConfigurationValue	uint8
	iConfiguration		uint8
	bmAttributes		uint8
	bMaxPower		uint8
}

ConfigDescriptor implements the standard USB configuration descriptor.

Table 9-10. Standard Configuration Descriptor bLength, bDescriptorType, wTotalLength, bNumInterfaces, bConfigurationValue, iConfiguration bmAttributes, bMaxPower

func (ConfigDescriptor) Bytes

func (d ConfigDescriptor) Bytes() []byte

Bytes returns ConfigDescriptor data.

type DeviceDescriptor

type DeviceDescriptor struct {
	bLength			uint8	// 18
	bDescriptorType		uint8	// 1 USB_DEVICE_DESCRIPTOR_TYPE
	bcdUSB			uint16	// 0x200
	bDeviceClass		uint8
	bDeviceSubClass		uint8
	bDeviceProtocol		uint8
	bMaxPacketSize0		uint8	// Packet 0
	idVendor		uint16
	idProduct		uint16
	bcdDevice		uint16	// 0x100
	iManufacturer		uint8
	iProduct		uint8
	iSerialNumber		uint8
	bNumConfigurations	uint8
}

DeviceDescriptor implements the USB standard device descriptor.

Table 9-8. Standard Device Descriptor bLength, bDescriptorType, bcdUSB, bDeviceClass, bDeviceSubClass, bDeviceProtocol, bMaxPacketSize0, idVendor, idProduct, bcdDevice, iManufacturer, iProduct, iSerialNumber, bNumConfigurations */

func (DeviceDescriptor) Bytes

func (d DeviceDescriptor) Bytes() []byte

Bytes returns DeviceDescriptor data

type EndpointDescriptor

type EndpointDescriptor struct {
	bLength			uint8	// 7
	bDescriptorType		uint8	// 5
	bEndpointAddress	uint8
	bmAttributes		uint8
	wMaxPacketSize		uint16
	bInterval		uint8
}

EndpointDescriptor implements the standard USB endpoint descriptor.

Table 9-13. Standard Endpoint Descriptor bLength, bDescriptorType, bEndpointAddress, bmAttributes, wMaxPacketSize, bInterval

func (EndpointDescriptor) Bytes

func (d EndpointDescriptor) Bytes() []byte

Bytes returns EndpointDescriptor data.

type I2C

type I2C struct {
	Bus *nrf.TWI_Type
}

I2C on the NRF.

func (I2C) Configure

func (i2c I2C) Configure(config I2CConfig)

Configure is intended to setup the I2C interface.

func (I2C) ReadRegister

func (i2c I2C) ReadRegister(address uint8, register uint8, data []byte) error

ReadRegister transmits the register, restarts the connection as a read operation, and reads the response.

Many I2C-compatible devices are organized in terms of registers. This method is a shortcut to easily read such registers. Also, it only works for devices with 7-bit addresses, which is the vast majority.

func (I2C) Tx

func (i2c I2C) Tx(addr uint16, w, r []byte) (err error)

Tx does a single I2C transaction at the specified address. It clocks out the given address, writes the bytes in w, reads back len® bytes and stores them in r, and generates a stop condition on the bus.

func (I2C) WriteRegister

func (i2c I2C) WriteRegister(address uint8, register uint8, data []byte) error

WriteRegister transmits first the register and then the data to the peripheral device.

Many I2C-compatible devices are organized in terms of registers. This method is a shortcut to easily write to such registers. Also, it only works for devices with 7-bit addresses, which is the vast majority.

type I2CConfig

type I2CConfig struct {
	Frequency	uint32
	SCL		Pin
	SDA		Pin
}

I2CConfig is used to store config info for I2C.

type IADDescriptor

type IADDescriptor struct {
	bLength			uint8	// 8
	bDescriptorType		uint8	// 11
	bFirstInterface		uint8
	bInterfaceCount		uint8
	bFunctionClass		uint8
	bFunctionSubClass	uint8
	bFunctionProtocol	uint8
	iFunction		uint8
}

IADDescriptor is an Interface Association Descriptor, which is used to bind 2 interfaces together in CDC composite device.

Standard Interface Association Descriptor: bLength, bDescriptorType, bFirstInterface, bInterfaceCount, bFunctionClass, bFunctionSubClass, bFunctionProtocol, iFunction

func (IADDescriptor) Bytes

func (d IADDescriptor) Bytes() []byte

Bytes returns IADDescriptor data.

type InterfaceDescriptor

type InterfaceDescriptor struct {
	bLength			uint8	// 9
	bDescriptorType		uint8	// 4
	bInterfaceNumber	uint8
	bAlternateSetting	uint8
	bNumEndpoints		uint8
	bInterfaceClass		uint8
	bInterfaceSubClass	uint8
	bInterfaceProtocol	uint8
	iInterface		uint8
}

InterfaceDescriptor implements the standard USB interface descriptor.

Table 9-12. Standard Interface Descriptor bLength, bDescriptorType, bInterfaceNumber, bAlternateSetting, bNumEndpoints, bInterfaceClass, bInterfaceSubClass, bInterfaceProtocol, iInterface

func (InterfaceDescriptor) Bytes

func (d InterfaceDescriptor) Bytes() []byte

Bytes returns InterfaceDescriptor data.

type MSCDescriptor

type MSCDescriptor struct {
	msc	InterfaceDescriptor
	in	EndpointDescriptor
	out	EndpointDescriptor
}

MSCDescriptor is not used yet.

type PWM

type PWM struct {
	Pin Pin
}

func (PWM) Configure

func (pwm PWM) Configure()

Configure configures a PWM pin for output.

func (PWM) Set

func (pwm PWM) Set(value uint16)

Set turns on the duty cycle for a PWM pin using the provided value.

type Pin

type Pin uint8

Pin is a single pin on a chip, which may be connected to other hardware devices. It can either be used directly as GPIO pin or it can be used in other peripherals like ADC, I2C, etc.

func (Pin) Configure

func (p Pin) Configure(config PinConfig)

Configure this pin with the given configuration.

func (Pin) Get

func (p Pin) Get() bool

Get returns the current value of a GPIO pin.

func (Pin) High

func (p Pin) High()

High sets this GPIO pin to high, assuming it has been configured as an output pin. It is hardware dependent (and often undefined) what happens if you set a pin to high that is not configured as an output pin.

func (Pin) Low

func (p Pin) Low()

Low sets this GPIO pin to low, assuming it has been configured as an output pin. It is hardware dependent (and often undefined) what happens if you set a pin to low that is not configured as an output pin.

func (Pin) PortMaskClear

func (p Pin) PortMaskClear() (*uint32, uint32)

Return the register and mask to disable a given port. This can be used to implement bit-banged drivers.

func (Pin) PortMaskSet

func (p Pin) PortMaskSet() (*uint32, uint32)

Return the register and mask to enable a given GPIO pin. This can be used to implement bit-banged drivers.

func (Pin) Set

func (p Pin) Set(high bool)

Set the pin to high or low. Warning: only use this on an output pin!

func (Pin) SetInterrupt

func (p Pin) SetInterrupt(change PinChange, callback func(Pin)) error

SetInterrupt sets an interrupt to be executed when a particular pin changes state. The pin should already be configured as an input, including a pull up or down if no external pull is provided.

This call will replace a previously set callback on this pin. You can pass a nil func to unset the pin change interrupt. If you do so, the change parameter is ignored and can be set to any value (such as 0).

type PinChange

type PinChange uint8

type PinConfig

type PinConfig struct {
	Mode PinMode
}

type PinMode

type PinMode uint8

type RingBuffer

type RingBuffer struct {
	rxbuffer	[bufferSize]volatile.Register8
	head		volatile.Register8
	tail		volatile.Register8
}

RingBuffer is ring buffer implementation inspired by post at https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php

func (*RingBuffer) Clear

func (rb *RingBuffer) Clear()

Clear resets the head and tail pointer to zero.

func (*RingBuffer) Get

func (rb *RingBuffer) Get() (byte, bool)

Get returns a byte from the buffer. If the buffer is empty, the method will return a false as the second value.

func (*RingBuffer) Put

func (rb *RingBuffer) Put(val byte) bool

Put stores a byte in the buffer. If the buffer is already full, the method will return false.

func (*RingBuffer) Used

func (rb *RingBuffer) Used() uint8

Used returns how many bytes in buffer have been used.

type SPI

type SPI struct {
	Bus *nrf.SPI_Type
}

SPI on the NRF.

func (SPI) Configure

func (spi SPI) Configure(config SPIConfig)

Configure is intended to setup the SPI interface.

func (SPI) Transfer

func (spi SPI) Transfer(w byte) (byte, error)

Transfer writes/reads a single byte using the SPI interface.

func (SPI) Tx

func (spi SPI) Tx(w, r []byte) error

Tx handles read/write operation for SPI interface. Since SPI is a syncronous write/read interface, there must always be the same number of bytes written as bytes read. The Tx method knows about this, and offers a few different ways of calling it.

This form sends the bytes in tx buffer, putting the resulting bytes read into the rx buffer. Note that the tx and rx buffers must be the same size:

    spi.Tx(tx, rx)

This form sends the tx buffer, ignoring the result. Useful for sending “commands” that return zeros until all the bytes in the command packet have been received:

    spi.Tx(tx, nil)

This form sends zeros, putting the result into the rx buffer. Good for reading a “result packet”:

    spi.Tx(nil, rx)

type SPIConfig

type SPIConfig struct {
	Frequency	uint32
	SCK		Pin
	SDO		Pin
	SDI		Pin
	LSBFirst	bool
	Mode		uint8
}

SPIConfig is used to store config info for SPI.

type UART

type UART struct {
	Buffer *RingBuffer
}

UART on the NRF.

func (UART) Buffered

func (uart UART) Buffered() int

Buffered returns the number of bytes currently stored in the RX buffer.

func (UART) Configure

func (uart UART) Configure(config UARTConfig)

Configure the UART.

func (UART) Read

func (uart UART) Read(data []byte) (n int, err error)

Read from the RX buffer.

func (UART) ReadByte

func (uart UART) ReadByte() (byte, error)

ReadByte reads a single byte from the RX buffer. If there is no data in the buffer, returns an error.

func (UART) Receive

func (uart UART) Receive(data byte)

Receive handles adding data to the UART’s data buffer. Usually called by the IRQ handler for a machine.

func (UART) SetBaudRate

func (uart UART) SetBaudRate(br uint32)

SetBaudRate sets the communication speed for the UART.

func (UART) Write

func (uart UART) Write(data []byte) (n int, err error)

Write data to the UART.

func (UART) WriteByte

func (uart UART) WriteByte(c byte) error

WriteByte writes a byte of data to the UART.

type UARTConfig

type UARTConfig struct {
	BaudRate	uint32
	TX		Pin
	RX		Pin
}

type USBCDC

type USBCDC struct {
	Buffer		*RingBuffer
	interrupt	interrupt.Interrupt
}

USBCDC is the USB CDC aka serial over USB interface on the nRF52840

func (USBCDC) Buffered

func (usbcdc USBCDC) Buffered() int

Buffered returns the number of bytes currently stored in the RX buffer.

func (*USBCDC) Configure

func (usbcdc *USBCDC) Configure(config UARTConfig)

Configure the USB CDC interface. The config is here for compatibility with the UART interface.

func (USBCDC) DTR

func (usbcdc USBCDC) DTR() bool

func (USBCDC) RTS

func (usbcdc USBCDC) RTS() bool

func (USBCDC) Read

func (usbcdc USBCDC) Read(data []byte) (n int, err error)

Read from the RX buffer.

func (USBCDC) ReadByte

func (usbcdc USBCDC) ReadByte() (byte, error)

ReadByte reads a single byte from the RX buffer. If there is no data in the buffer, returns an error.

func (USBCDC) Receive

func (usbcdc USBCDC) Receive(data byte)

Receive handles adding data to the UART’s data buffer. Usually called by the IRQ handler for a machine.

func (USBCDC) Write

func (usbcdc USBCDC) Write(data []byte) (n int, err error)

Write data to the USBCDC.

func (USBCDC) WriteByte

func (usbcdc USBCDC) WriteByte(c byte) error

WriteByte writes a byte of data to the USB CDC interface.