Class: OrigenSpi::Driver

Inherits:
Object
  • Object
show all
Includes:
Origen::Model
Defined in:
lib/origen_spi/driver.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Driver

options hash can configure

Examples:

options = {
  sclk_pin: dut.pin(:p1),
  mosi_pin: dut.pin(:p2),
  miso_pin: dut.pin(:p3),
  ss_pin: dut.pin(:p4),
  clk_format: :rl,
  ss_active: 0,
  clk_wait_time: {time_in_cycles: 2},
  clk_multiple: 2,
  miso_compare_cycle: 1,
  data_order: :msb0
}
spi = OrigenSpi::Driver.new(options)


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# File 'lib/origen_spi/driver.rb', line 87

def initialize(options = {})
  options = {
    sclk_pin:      nil,
    mosi_pin:      nil,
    miso_pin:      nil,
    ss_pin:        nil,
    clk_format:    :nr,
    ss_active:     0,
    clk_wait_time: { time_in_us: 0 },
    clk_multiple:  2,
    data_order:    :msb0
  }.merge(options)

  @sclk_pin = options[:sclk_pin]
  @mosi_pin = options[:mosi_pin]
  @miso_pin = options[:miso_pin]
  @ss_pin = options[:ss_pin]
  @clk_format = options[:clk_format]
  @ss_active = options[:ss_active]
  @clk_wait_time = options[:clk_wait_time]
  @clk_multiple = options[:clk_multiple]
  @miso_compare_cycle = options[:miso_compare_cycle] ? options[:miso_compare_cycle] : @clk_multiple - 1
  @data_order = options[:data_order]
  @settings_validated = false
end

Instance Attribute Details

#clk_format ⇒ Object

clock format

available options are:

:rl   # return low - data changes while sclk is low, latches on rising edge
:rh   # return high

Examples:

spi_instance.clk_format = :rl


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# File 'lib/origen_spi/driver.rb', line 35

def clk_format
  @clk_format
end

#clk_multiple ⇒ Object

number of tester cycles per spi clock



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# File 'lib/origen_spi/driver.rb', line 53

def clk_multiple
  @clk_multiple
end

#clk_wait_time ⇒ Object

time between ss_active and the first spi clock

hash containing the wait time

Examples:

spi_instance.clk_wait_time = {time_in_us: 0}        # no delay
spi_instance.clk_wait_time = {time_in_ms: 1}        # 1ms delay
spi_instance.clk_wait_time = {time_in_cycles: 2}    # 2 cycle delay


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# File 'lib/origen_spi/driver.rb', line 50

def clk_wait_time
  @clk_wait_time
end

#data_order ⇒ Object

data order

available options are:

:msb0 - MSB is shifted first
:lsb0

Examples:

spi_instance.data_order = :lsb0


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# File 'lib/origen_spi/driver.rb', line 66

def data_order
  @data_order
end

#miso_compare_cycle ⇒ Object

cycle on which miso compares are placed (0 is the first cycle)



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# File 'lib/origen_spi/driver.rb', line 56

def miso_compare_cycle
  @miso_compare_cycle
end

#miso_pin ⇒ Object

Dut pin that serves as the master in slave out

Examples:

spi_instance.miso_pin = dut.pin(:p3)


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# File 'lib/origen_spi/driver.rb', line 18

def miso_pin
  @miso_pin
end

#mosi_pin ⇒ Object

Dut pin that serves as the master out slave in pin

Examples:

spi_instance.mosi_pin = dut.pin(:p2)


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# File 'lib/origen_spi/driver.rb', line 13

def mosi_pin
  @mosi_pin
end

#sclk_pin ⇒ Object

Dut pin that serves as the spi clock

Examples:

spi_instance.sclk_pin = dut.pin(:p1)


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# File 'lib/origen_spi/driver.rb', line 8

def sclk_pin
  @sclk_pin
end

#settings_validated ⇒ Object (readonly)

internal attribute



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# File 'lib/origen_spi/driver.rb', line 69

def settings_validated
  @settings_validated
end

#ss_active ⇒ Object

pin state corresponding to slave select active

Examples:

spi_instance.ss_active = 0


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# File 'lib/origen_spi/driver.rb', line 40

def ss_active
  @ss_active
end

#ss_pin ⇒ Object

Dut pin that serves as the slave select

Examples:

spi_instance.ss_pin = dut.pin(:p4)
spi_instance.ss_pin = nil   # no ss pin


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# File 'lib/origen_spi/driver.rb', line 25

def ss_pin
  @ss_pin
end

Instance Method Details

#build_input_packet(options) ⇒ Object

Build the input packet

This is an internal method used by the shift method



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# File 'lib/origen_spi/driver.rb', line 333

def build_input_packet(options)
  in_reg = Origen::Registers::Reg.dummy(options[:size])
  if options[:master_in].respond_to?(:data)
    in_reg.copy_all(options[:master_in])
  else
    unless options[:master_in].nil?
      in_reg.write options[:master_in]
      in_reg.read
    end
  end
  in_reg
end

#build_output_packet(options) ⇒ Object

Build the shift out packet

This is an internal method used by the shift method



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# File 'lib/origen_spi/driver.rb', line 320

def build_output_packet(options)
  out_reg = Origen::Registers::Reg.dummy(options[:size])
  if options[:master_out].respond_to?(:data)
    out_reg.copy_all(options[:master_out])
  else
    out_reg.write options[:master_out]
  end
  out_reg
end

#cycle(overlay_options = {}) ⇒ Object

Internal method

Issue a tester cycle, conditionally with overlay options supplied



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# File 'lib/origen_spi/driver.rb', line 313

def cycle(overlay_options = {})
  overlay_options == {} ? tester.cycle : (tester.cycle overlay: overlay_options)
end

#handle_miso(c, bit) ⇒ Object

Internal method

Set the state of miso



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# File 'lib/origen_spi/driver.rb', line 299

def handle_miso(c, bit)
  unless @miso_pin.nil?
    if c == @miso_compare_cycle
      @miso_pin.assert bit.data if bit.is_to_be_read?
      tester.store_next_cycle @miso_pin if bit.is_to_be_stored?
    else
      @miso_pin.dont_care
    end
  end
end

#sclk_cycle ⇒ Object

Run a spi clock cycle

This method can be used to clock the spi port without specifying shift data



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# File 'lib/origen_spi/driver.rb', line 213

def sclk_cycle
  validate_settings
  cc 'OrigenSpi::Driver - Issue a clock cycle'
  @sclk_pin.restore_state do
    @sclk_pin.drive @clk_format == :rl ? 0 : 1
    @half_cycle.times { tester.cycle }
    @sclk_pin.drive @clk_format == :rl ? 1 : 0
    @half_cycle.upto(@clk_multiple - 1) { tester.cycle }
  end
end

#shift(options = {}) ⇒ Object

Shift a spi packet

Overlay and capture is specified through reg.overlay and reg.store

Examples:

spi_instance.shift master_out: out_reg, master_in: in_cmp_reg
spi_instance.shift master_out: 0x7a, size: 32
spi_instance.shift master_in: in_cmp_reg


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# File 'lib/origen_spi/driver.rb', line 234

def shift(options = {})
  options = {
    master_out: 0
  }.merge(options)

  validate_settings
  options = validate_options(options)
  out_reg = build_output_packet(options).bits
  in_reg = build_input_packet(options).bits

  # reverse bit order if :msb0
  if @data_order == :msb0
    out_reg = out_reg.reverse
    in_reg = in_reg.reverse
  end

  # set ss active
  @ss_pin.drive @ss_active unless @ss_pin.nil?

  # apply wait time if requested
  tester.wait @clk_wait_time unless @clk_wait_time == { time_in_us: 0 }

  # now do the shifting
  0.upto(out_reg.size - 1) do |bit|
    # park the clock
    @sclk_pin.drive @clk_format == :rl ? 0 : 1
    @miso_pin.dont_care unless @miso_pin.nil?

    # setup the bit to be driven, prep for overlay if requested
    overlay_options = {}
    unless @mosi_pin.nil?
      @mosi_pin.drive out_reg[bit].data
      if out_reg[bit].has_overlay?
        overlay_options[:pins] = @mosi_pin
        overlay_options[:overlay_str] = out_reg[bit].overlay_str
      end
    end

    # advance to clock active edge
    @half_cycle.times do |c|
      handle_miso c, in_reg[bit]
      cycle overlay_options
      overlay_options[:change_data] = false unless overlay_options == {}
    end

    # drive the clock to active
    @sclk_pin.drive @clk_format == :rl ? 1 : 0

    # advance to the end of the sclk cycle checking for appropriate miso compare placement
    @half_cycle.upto(@clk_multiple - 1) do |c|
      handle_miso c, in_reg[bit]
      cycle overlay_options
    end
  end

  # park the clock, mask miso, clear ss
  @sclk_pin.drive @clk_format == :rl ? 0 : 1
  @miso_pin.dont_care unless @miso_pin.nil?
  @mosi_pin.drive 0 unless @mosi_pin.nil?
  @ss_pin.drive @ss_active == 1 ? 0 : 1 unless @ss_pin.nil?
end

#validate_options(options) ⇒ Object

Internal method that logs errors in options passed to the shift method



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# File 'lib/origen_spi/driver.rb', line 347

def validate_options(options)
  # check that size of the packet can be determined
  unless options[:size]
    options[:size] = options[:master_in].size if options[:master_in].respond_to?(:data)
  end
  unless options[:size]
    options[:size] = options[:master_out].size if options[:master_out].respond_to?(:data)
  end
  unless options[:size]
    Origen.log.error "OrigenSpi::Driver can't determine the packet size"
    exit
  end
  options
end

#validate_settings ⇒ Object

Check settings



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# File 'lib/origen_spi/driver.rb', line 176

def validate_settings
  unless @settings_validated
    settings_valid = true

    # check that clock and miso are provided
    unless @sclk_pin.is_a?(Origen::Pins::Pin)
      settings_valid = false
      Origen.log.error 'OrigenSpi::Driver.sclk_pin must be an Origen pin object'
    end

    unless @clk_format == :rl || @clk_format == :rh
      settings_valid = false
      Origen.log.error 'OrigenSpi::Driver.clk_format must be one of :rl, :rh'
    end

    unless @ss_active == 0 || @ss_active == 1
      settings_valid = false
      Origen.log.error 'OrigenSpi::Driver.ss_active must be either 0 or 1'
    end

    @clk_multiple = 1 if @clk_multiple < 1
    @half_cycle = @clk_multiple / 2

    @miso_compare_cycle = @clk_multiple - 1 if @miso_compare_cycle > @clk_multiple - 1

    unless @data_order == :msb0 || @data_order == :lsb0
      settings_valid = false
      Origen.log.error 'OrigenSpi::Driver.data_order must be either :msb0 or :lsb0'
    end

    @settings_validated = settings_valid
  end
end