Class: Denko::DigitalIO::PCF8574

Inherits:
Object
  • Object
show all
Includes:
Behaviors::BoardProxy, Behaviors::Lifecycle, I2C::Peripheral
Defined in:
lib/denko/digital_io/pcf8574.rb

Constant Summary collapse

I2C_ADDRESS =

Default I2C address. Override with i2c_address: key in initialize hash.

0x3F
I2C_FREQUENCY = 
400_000

Constants included from Behaviors::Lifecycle

Behaviors::Lifecycle::CALLBACK_METHODS

Constants included from I2C::Peripheral

I2C::Peripheral::I2C_REPEATED_START

Constants included from Behaviors::Reader

Behaviors::Reader::READ_WAIT_TIME

Instance Attribute Summary collapse

Attributes included from I2C::Peripheral

#i2c_frequency, #i2c_repeated_start

Attributes included from Behaviors::Component

#board, #params

Instance Method Summary collapse

Methods included from Behaviors::BoardProxy

#analog_read_high, #analog_write_high, #convert_pin, #high, #low, #start_read

Methods included from Behaviors::Subcomponents

#add_component, #add_hw_i2c, #add_hw_spi, #add_single_pin, #components, #hw_i2c_comps, #hw_spi_comps, #remove_component, #remove_hw_i2c, #remove_hw_spi, #remove_single_pin, #single_pin_components

Methods included from Behaviors::Lifecycle

included

Methods included from I2C::Peripheral

#address, #i2c_default, #i2c_read, #i2c_read_raw, #i2c_write

Methods included from Behaviors::Reader

#_read, #read, #read_busy?, #read_nb, #read_raw, #read_using, #update

Methods included from Behaviors::Callbacks

#add_callback, #callbacks, #pre_callback_filter, #remove_callback, #update

Methods included from Behaviors::State

#update_state

Methods included from Behaviors::BusPeripheralAddressed

#address

Methods included from Behaviors::BusPeripheral

#atomically

Methods included from Behaviors::Component

#initialize, #micro_delay

Instance Attribute Details

#bytes ⇒ Object

Default registers to 1 byte, or 8 pins when used as Board Proxy. Can be ignored if reading / writing the register directly.



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# File 'lib/denko/digital_io/pcf8574.rb', line 82

def bytes
  @bytes = params[:bytes] || 1
end

Instance Method Details

#bit_set(pin, value) ⇒ Object 



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# File 'lib/denko/digital_io/pcf8574.rb', line 102

def bit_set(pin, value)
  @state_mutex.lock
  @state[pin] = value
  @state_mutex.unlock
  value
end

#digital_read(pin) ⇒ Object 



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# File 'lib/denko/digital_io/pcf8574.rb', line 67

def digital_read(pin)
  state[pin]
end

#digital_write(pin, value) ⇒ Object

Taken from SPI::Output Register.



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# File 'lib/denko/digital_io/pcf8574.rb', line 97

def digital_write(pin, value)
  bit_set(pin, value)
  write
end

#is_a_register? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/denko/digital_io/pcf8574.rb', line 71

def is_a_register?
  true
end

#pin_is_pwm?(pin) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/denko/digital_io/pcf8574.rb', line 109

def pin_is_pwm?(pin)
  false
end

#platform ⇒ Object

BoardProxy interface. Refactor maybe?



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# File 'lib/denko/digital_io/pcf8574.rb', line 55

def platform
  :pcf8574
end

#read_state ⇒ Object 



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# File 'lib/denko/digital_io/pcf8574.rb', line 42

def read_state
  @state_mutex.lock
  byte = i2c_read_raw(1)[0]
  8.times do |i|
    @state[i] = (byte >> i) & 0b1
  end
  @state_mutex.unlock
  @state
end

#set_pin_mode(pin, mode, options = {}) ⇒ Object 



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# File 'lib/denko/digital_io/pcf8574.rb', line 59

def set_pin_mode(pin, mode, options={})
  if mode == :output
    digital_write(pin, 0)
  else
    digital_write(pin, 1)
  end
end

#state ⇒ Object

When used as BoardProxy, store the state of each register pin as a 0 or 1 in an array that is (@bytes * 8) long.



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# File 'lib/denko/digital_io/pcf8574.rb', line 90

def state
  @state ||= Array.new(bytes*8) { 1 }
end

#write ⇒ Object 



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# File 'lib/denko/digital_io/pcf8574.rb', line 22

def write
  bytes = []
  @state_mutex.lock
  if @state != @previous_state
    @state.each_slice(8) do |slice|
      byte = 0
      slice.each_with_index do |bit, index|
        next unless bit
        byte |= (bit << index)
      end

      bytes.unshift byte
    end
    i2c_write bytes
    @previous_state = @state.dup
  end
  @state_mutex.unlock
  @state
end