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Cassini uses the Fixture's ESN (Serial Number chip or ID chip) to uniquely identify the Fixture definition and calibration data. A ESN can be loaded on a DUT Interface Board (DIB) to add DIB specific calibration information. This document describes what types of chips are suitable and how to use Cassini when designing your own Fixture or DIB. ESN chips can be serialized to allow multiple layers of calibration, useful for loading calibration offsets for DIBs and Fixtures. Cassini reads all chips connected to the S/N port and Guru is queried to retrieve the RiDibCal and RiFixtureCal guru objects (if any) for the serial number assigned to them. The fixture chip has a family code 20 (14H) or 45 (2CH). Any other family code can be used for the DIB.

  • Cassini requires Patch 137 or later (08/25/2011)
  • RIK0300A is available for DIBs or Fixtures without a Carrier.
  • RIFL Serial Number (8 digits) is included on all Fixture Carrier Boards (POD Carrier, RIFL Carrier, Active Carrier)

Assign a ESN with a RiFixtureCal or RiDIBCal:
  1. Attach Fixture/DIB with a fresh ESN to Cassini.
    IMPORTANT! Only one unknown ESN should be attached at a time (i.e. no RiDibCal or RiFixtureCal objects exist). RI recommends that the Fixture Cal be defined before the DIB Cal.
  2. Choose System > Check to scan for the new serial number.
  3. A red message window entry will appear similar to "No cal found for this esn: DSN################", where #### is the 16-digit unique serial number of the ESN chip.
  4. Choose System > Tester to to pen the Configuration window
  5. Choose Instrument > Add Fixture Def... (or Add Dib Def...)
  6. Choose Fixture or Dut Interface to select it.
  7. Choose Instrument > Calibration > Save to assign the serial number to the definition.
Note: The menu options for Test > Fixture Cal... and Test > Dut Interface Cal... in the main Cassini window select calibrations (RiDibCal, RiFixtureCal) objects, not definitions as you might expect.

ESN Chips

Maxim/Dallas 1 wire serial number chips that use parasitic power and work down to 2.9 volts - example: DS2401 or DS2431
(note: prior to patch 137 @ 8/25/11 11:58am, Fixture requires xx31 and DIB requires xx01)

Example Part: MAXIM SOT-223

Physical Wiring

POD Carriers and RIFL Carriers contain a serial number assigned by Guru that is an 8 digit ID. Connect the Fixture and DIB to the SN pins on the carrier to the ESN chip in parallel. Any GND or RTN pin will work to complete the circuit.

The Fixture and DIB S/N chips must be connected to the S/N pin (H10) on the Fixture DC Block. Connect pin H1 to one side of the DS2401 and H10 to the other.

Example: Serial IC shrink wrapped and mounted to fixture with zip ties

Connect the serial chip to the S/N port on the RIK0166A "FIX Block", included with RIK0151A "Cassini 16 Interface" and RIK0130A "Cassini 8 port Interface"
If using a Fixture with an Active Carrier, you should connect the S/N pins to the S/N jumpers on the Carrier. See the RIK part description for location information.

DUT Interface Boards (DIB) and Fixtures without a Carrier can use a Fixture Serial Number Chip (RIK0199A) connected to the S/N port on the DC Block.

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