bitbang

Documentation

Overview

Package bitbang implements conn by banging on the bits (GPIO pins).

This is not efficient but works around broken or missing drivers.

Index

• Constants
• type I2C
  • func New(clk gpio.PinIO, data gpio.PinIO, speedHz int) (*I2C, error)
  • func (i *I2C) Close() error
  • func (i *I2C) SCL() gpio.PinIO
  • func (i *I2C) SDA() gpio.PinIO
  • func (i *I2C) SetSpeed(hz int64) error
  • func (i *I2C) String() string
  • func (i *I2C) Tx(addr uint16, w, r []byte) error
• type SPI
  • func NewSPI(clk, mosi gpio.PinOut, miso gpio.PinIn, cs gpio.PinOut, speedHz int64) (*SPI, error)
  • func (s *SPI) CLK() gpio.PinOut
  • func (s *SPI) CS() gpio.PinOut
  • func (s *SPI) Close() error
  • func (s *SPI) Connect(maxHz int64, mode spi.Mode, bits int) error
  • func (s *SPI) Duplex() conn.Duplex
  • func (s *SPI) LimitSpeed(maxHz int64) error
  • func (s *SPI) MISO() gpio.PinIn
  • func (s *SPI) MOSI() gpio.PinOut
  • func (s *SPI) String() string
  • func (s *SPI) Tx(w, r []byte) error
  • func (s *SPI) TxPackets(p []spi.Packet) error
  • func (s *SPI) Write(d []byte) (int, error)
• Bugs

Constants

const SkipAddr uint16 = 0xFFFF

SkipAddr can be used to skip the address from being sent.

Types

type I2C

type I2C struct {
	// contains filtered or unexported fields
}

I2C represents an I²C master implemented as bit-banging on 2 GPIO pins.

func New

func New(clk gpio.PinIO, data gpio.PinIO, speedHz int) (*I2C, error)

New returns an object that communicates I²C over two pins.

BUG(maruel): It is close to working but not yet, the signal is incorrect during ACK.

It has two special features:

• Special address SkipAddr can be used to skip the address from being communicated
• An arbitrary speed can be used

func (*I2C) Close

func (i *I2C) Close() error

Close implements i2c.BusCloser.

func (*I2C) SCL

func (i *I2C) SCL() gpio.PinIO

SCL implements i2c.Pins.

func (*I2C) SDA

func (i *I2C) SDA() gpio.PinIO

SDA implements i2c.Pins.

func (*I2C) SetSpeed

func (i *I2C) SetSpeed(hz int64) error

SetSpeed implements i2c.Bus.

func (*I2C) String

func (i *I2C) String() string

func (*I2C) Tx

func (i *I2C) Tx(addr uint16, w, r []byte) error

Tx implements i2c.Bus.

type SPI

type SPI struct {
	// contains filtered or unexported fields
}

SPI represents a SPI master implemented as bit-banging on 3 or 4 GPIO pins.

func NewSPI

func NewSPI(clk, mosi gpio.PinOut, miso gpio.PinIn, cs gpio.PinOut, speedHz int64) (*SPI, error)

NewSPI returns an object that communicates SPI over 3 or 4 pins.

BUG(maruel): Completely untested.

cs can be nil.

func (*SPI) CLK

func (s *SPI) CLK() gpio.PinOut

CLK implements spi.Pins.

func (*SPI) CS

func (s *SPI) CS() gpio.PinOut

CS implements spi.Pins.

func (*SPI) Close

func (s *SPI) Close() error

Close implements spi.ConnCloser.

func (*SPI) Connect

func (s *SPI) Connect(maxHz int64, mode spi.Mode, bits int) error

Connect implements spi.Conn.

func (*SPI) Duplex

func (s *SPI) Duplex() conn.Duplex

Duplex implements spi.Conn.

func (*SPI) LimitSpeed

func (s *SPI) LimitSpeed(maxHz int64) error

LimitSpeed implements spi.ConnCloser.

func (*SPI) MISO

func (s *SPI) MISO() gpio.PinIn

MISO implements spi.Pins.

func (*SPI) MOSI

func (s *SPI) MOSI() gpio.PinOut

MOSI implements spi.Pins.

func (*SPI) String

func (s *SPI) String() string

func (*SPI) Tx

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

Tx implements spi.Conn.

BUG(maruel): Implement mode. BUG(maruel): Implement bits. BUG(maruel): Test if read works.

func (*SPI) TxPackets

func (s *SPI) TxPackets(p []spi.Packet) error

TxPackets implements spi.Conn.

func (*SPI) Write

func (s *SPI) Write(d []byte) (int, error)

Write implements io.Writer.

Notes

Bugs

• It is close to working but not yet, the signal is incorrect during ACK.

  It has two special features:

  • Special address SkipAddr can be used to skip the address from being communicated
  • An arbitrary speed can be used

• Implement mode.

• Implement bits.

• Test if read works.

• Completely untested.

  cs can be nil.