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Contents
module Denko
module SPI
class OutputRegister < BaseRegister
def before_initialize(options={})
super(options)
#
# When used as a board proxy, only write sate if @write_delay seconds
# have passed since this object last got input. Better for things like SSDs
# where many bits change in sequence, but not at exactly the same time.
#
@buffer_writes = true
@buffer_writes = false if options[:buffer_writes] == false
@write_delay = options[:write_delay] || 0.001
end
def after_initialize(options={})
write
end
#
# Overrides Peripheral#write to always write @state.
# Convert bit state to array of 0-255 integers (bytes) first.
#
def write
bytes = []
@state.each_slice(8) do |slice|
# Convert nils in the slice to zero.
zeroed = slice.map { |bit| bit.to_i }
# Each slice is 8 bits of a byte, with the lowest on the left.
# Reverse to reading order (lowest right) then join into string, and convert to integer.
byte = zeroed.reverse.join.to_i(2)
# Pack bytes in reverse order.
bytes.unshift byte
end
spi_write(bytes)
end
#
# BoardProxy interface
#
def digital_write(pin, value)
state[pin] = value # Might not be atomic?
@buffer_writes ? write_buffered(state) : write
end
def digital_read(pin)
state[pin]
end
#
# If acting as board, do writes in a separate thread and with small delay.
# Lets us catch multiple changed bits, like when hosting an SSD.
#
include Behaviors::Threaded
def write_buffered(old_state)
threaded do
sleep @write_delay
# Keep delaying if state has changed.
write if (old_state == state)
end
end
end
end
end
Version data entries
7 entries across 7 versions & 1 rubygems