Module: Adept::JTAG::TAPStates::TAPState

Defined in:
lib/adept/jtag/tap_state.rb

Overview

Base for all Test Access Port states.

Instance Method Summary collapse

Instance Method Details

#next_hop_towards(state) ⇒ Object

Determines the next value which should be present on the mode-set line to get to the given state.



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# File 'lib/adept/jtag/tap_state.rb', line 28

def next_hop_towards(state)

  #Get a refrence to the state module indicated by the TowardsZeroIfStateIs metaconstant.
  towards_zero = TAPStates.const_get(self::NextState[0])
  towards_one  = TAPStates.const_get(self::NextState[1])

  #Determine if a next-hop of one would cause us to get stuck in a loop.
  towards_one_would_cause_loop = (towards_one == self || self::NextState[1] == :Reset)

  #If the next state would be achievable by providing a hop of zero, 
  #or a hop of one would cause a loop, then the next hop should be zero.
  #
  #Otherwise, the next hop should be '1'.
  ((state == towards_zero) || towards_one_would_cause_loop) ? [0, towards_zero] : [1, towards_one]
end

#next_state(value) ⇒ Object

Returns the successor to the current state, given an input value.



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# File 'lib/adept/jtag/tap_state.rb', line 14

def next_state(value)

  #Get the name of the module which describes the successor state...
  state = self::NextState[value]

  #... and get a reference to the module itself.
  TAPStates.const_get(state)

end