Class: Rbuspirate::Interfaces::I2C

Inherits:
Abstract
  • Object
show all
Defined in:
lib/rbuspirate/interfaces/i2c.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Abstract

#configure_peripherals

Constructor Details

#initialize(serial, bup) ⇒ I2C

Returns a new instance of I2C.



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 11

def initialize(serial, bup)
  raise 'Bus pirate must be in i2c mode' unless bup.mode == :i2c

  @le_port = serial
  set_speed(:'400khz')
end

Instance Attribute Details

#aux ⇒ Object (readonly)

Returns the value of attribute aux.



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 9

def aux
  @aux
end

#cs ⇒ Object (readonly)

Returns the value of attribute cs.



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 9

def cs
  @cs
end

#power ⇒ Object (readonly)

Returns the value of attribute power.



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 9

def power
  @power
end

#pullup ⇒ Object (readonly)

Returns the value of attribute pullup.



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 9

def pullup
  @pullup
end

#speed ⇒ Object

Returns the value of attribute speed.



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 9

def speed
  @speed
end

Instance Method Details

#bulk_write(data, ack_timeout: Timeouts::I2C::SLAVE_ACKNACK) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/rbuspirate/interfaces/i2c.rb', line 67

def bulk_write(data, ack_timeout: Timeouts::I2C::SLAVE_ACKNACK)
  raise ArgumentError, 'data must be String instance' unless data.instance_of?(String)

  if !data.instance_of?(String) || data.instance_of?(String) && data.empty?
    raise ArgumentError, 'Bad data argument'
  end
  raise ArgumentError, 'Data is too long' if data.bytesize > 16

  bit_bulk_write = Commands::I2C::PREPARE_WRITE | data.bytesize - 1
  simplex_command(
    bit_bulk_write.chr,
    Timeouts::I2C::PREPARE_WRITE,
    'Unable to prepare write mode'
  )
  ack_array = []
  data.each_byte do |data_byte|
    @le_port.write(data_byte.chr)
    Timeout.timeout(ack_timeout) do
      ack_array << case @le_port.read(1).ord
                   when 0
                     :ack
                   when 1
                     :nack
                   else
                     raise 'Unknown bytewrite response'
                   end
      yield(ack_array.last) if block_given?
    end
  end
  ack_array.freeze
end

#read(bytes = 1, auto_ack: true, auto_nack: true, readbyte_timeout: Timeouts::I2C::READ) ⇒ Object 



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 54

def read(bytes = 1, auto_ack: true, auto_nack: true, readbyte_timeout: Timeouts::I2C::READ)
  result = ''.dup.b
  bytes.times do |t|
    @le_port.write(Commands::I2C::READBYTE.chr)
    Timeout.timeout(readbyte_timeout) do
      result << @le_port.read(1)
    end
    send_ack if auto_ack && t + 1 != bytes
    send_nack if auto_nack && t + 1 == bytes
  end
  result
end

#send_ack ⇒ Object 



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 38

def send_ack
  simplex_command(
    Commands::I2C::Flow::ACK,
    Timeouts::I2C::ACKNACK,
    'Unable to sent ack'
  )
end

#send_nack ⇒ Object 



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 46

def send_nack
  simplex_command(
    Commands::I2C::Flow::NACK,
    Timeouts::I2C::ACKNACK,
    'Unable to sent nack'
  )
end

#send_start ⇒ Object 



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 22

def send_start
  simplex_command(
    Commands::I2C::Flow::START,
    Timeouts::I2C::STARTSTOP,
    'Unable to sent start bit'
  )
end

#send_stop ⇒ Object 



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# File 'lib/rbuspirate/interfaces/i2c.rb', line 30

def send_stop
  simplex_command(
    Commands::I2C::Flow::STOP,
    Timeouts::I2C::STARTSTOP,
    'Unable to sent stop bit'
  )
end

#write_then_read(data, expected_bytes = 0, succes_timeout: Timeouts::I2C::WRITE_THEN_READ_S, allow_zerobyte: false) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/rbuspirate/interfaces/i2c.rb', line 99

def write_then_read(
  data, expected_bytes = 0,
  succes_timeout: Timeouts::I2C::WRITE_THEN_READ_S,
  allow_zerobyte: false
)
  raise ArgumentError, 'Bad data type' unless data.instance_of?(String)
  raise ArgumentError, 'Data is too long' if data.bytesize > 4096
  raise ArgumentError, 'Bad expected_bytes type' unless expected_bytes.instance_of?(Integer)
  raise ArgumentError, 'Bad expected_bytes value' if expected_bytes.negative? || expected_bytes > 4096

  binary_command = Commands::I2C::WRITE_THEN_READ.chr +
                   [data.bytesize, expected_bytes].pack('S>S>') +
                   data
  @le_port.write(binary_command)
  result = nil
  # So fucking ugly
  begin
    Timeout.timeout(succes_timeout) do
      result = @le_port.read(1)
    end
  rescue Timeout::Error
    return false
  end
  return false if allow_zerobyte && result.ord.zero?
  raise 'Write failed' if result.ord.zero?
  if expected_bytes != 0
    Timeout.timeout(Timeouts::I2C::WRITE_THEN_READ_D) do
      result = @le_port.read(expected_bytes)
    end
    result
  else
    true
  end
end