Models

Power Domains

Power domains are modeled from the Design side, not from an ATE perspective. Power domains are not the same thing as power pins, rather power domains contain (indirectly) three types of pins:

1. Signal
2. Power
3. Ground

The idea behind modeling power domains is to provide a source of truth for the voltages various pins are programmed to on the ATE. There is no native pin levels API yet in Origen but users do create ATE levels using the Origen compiler. Prior to the development of PowerDomains, applications would likely use the Origen::Parameters module to store pin levels. The advantage of using PowerDomains is that all pins get a single source of truth for their programmed value.

Here is an example of the PowerDomain API:

add_power_domain :vdd do |domain|
  domain.description = 'CPU Core Complex'
  domain.nominal_voltage = 0.9.V
  domain.unit_voltage_range = 0.7.V..1.1.V
end
add_power_domain :vdda do |domain|
  domain.description = 'PLL'
  domain.nominal_voltage = 1.2.V
  domain.unit_voltage_range = 1.08.V..1.32.V
end
add_power_domain :vccsoc do |domain|
  domain.description = 'SoC'
  domain.nominal_voltage = 1.5.V
  domain.unit_voltage_range = 1.35.V..1.65.V
end

Now we can interact with the power domains using the top level DUT.

    $dut.power_domains # => [:vdd, :vdda, :vccsoc]
    $dut.power_domains(:vdd).description # => "CPU Core Complex"
    $dut.power_domains(:vdd).nominal_voltage # => 1.0.V
    $dut.power_domains(:vdd).range # => (0.7.V..1.1.V)

Typically in Origen, models own things directly, but in the case of power domains, they ‘own’ pins indirectly. Most apps instantiate pins to the top level DUT so the PowerDomains module was written to deal with that reality, versus asking apps to instantiate pins within a power domain. In order for a power domain to be aware of the pins it ‘owns’, pins must set the ‘supply’ pin attribute.

Let’s define some pins, for the :vdd power domain, that have the supply attribute defined.

  VDD_SIGNAL_PINS = [:pin1, :pin2, :pin3]
  VDD_POWER_PINS = [:vdd1, :vdd2, :vdd3]
  VDD_GND_PINS = [:vss1, :vss2, :vss3]

  def initialize
    VDD_SIGNAL_PINS.each do |p|
      $dut.add_pin p do |pin|
        pin.supply = :vdd
      end
    end
    VDD_POWER_PINS.each do |p|
      $dut.add_power_pin p do |pin|
        pin.supply = :vdd
      end
    end
    VDD_GND_PINS.each do |p|
      $dut.add_ground_pin p do |pin|
        pin.supply = :vdd
      end
    end
  end

Here are some methods available to interact with the pins associated with a power domain.

    $dut.power_domains(:vdd).signal_pins # => [:pin1, :pin2, :pin3]
    $dut.power_domains(:vdd).power_pins # => [:vdd1, :vdd2, :vdd3]
    $dut.power_domains(:vdd).ground_pins # => [:vss1, :vss2, :vss3]
    $dut.power_domains(:vdd).has_pin?(:vdd1) # => true
    $dut.power_domains(:vdd).pin_type(:vdd1) # => :power
    $dut.power_domains(:vdd).has_power_pin?(:vdd1) # => true
    $dut.power_domains(:vdd).has_pin?(:pin1) # => true
    $dut.power_domains(:vdd).pin_type(:pin1) # => :signal
    $dut.power_domains(:vdd).has_signal_pin?(:pin1) # => true
    $dut.power_domains(:vdd).has_pin?(:vss1) # => true
    $dut.power_domains(:vdd).pin_type(:vss1) # => :ground
    $dut.power_domains(:vdd).has_ground_pin?(:vss1) # => true
    $dut.power_domains(:vdda).signal_pins # => []
    $dut.power_domains(:vdda).power_pins # => []
    $dut.power_domains(:vdda).ground_pins # => []
    $dut.power_domains(:vdda).has_pin?(:vdd1) # => false

After a power domain is instantiated, its setpoint or value is nil by default. This behavior is by design, such that the user could define chip modes or parameter contexts that provide scope for a group of power domain values. Here are some examples of setting power domain setpoints/values.

  $dut.power_domains(:vdd).setpoint = 0.72.V
  $dut.power_domains(:vdda).setpoint = 1.10.V
  $dut.power_domains(:vccsoc).setpoint = 1.37.V

A little about the attribute ‘unit_voltage_range’. If a power domain has this attribute set to :fixed, then it means all units will see the eact same voltage when the device is powered up. If this attribute is set to a Range, then it means each device can power-up to a unique voltage, based on a permanently programmed value stored within the device (e.g. using e-fuses).