MIL-STD-1553

Production Test Plan for Remote Terminals

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Table of Contents

PARAGRAPH TEST
1. SCOPE
1.1 General
1.2 Application
2. APPLICABLE DOCUMENTS
2.1 Standards, Military
2.2 Other Documents
3. DEFINITIONS
3.1 Responses
3.1.1 BCR
3.1.2 BUSY
3.1.3 CS
3.1.4 DBA
3.1.5 ME
3.1.6 NR
3.1.7 Respond in Form
3.1.8 SF
3.1.9 TF
3.2 Other Definitions
3.2.1 UUT
3.2.2 RT
3.2.3 BC
4. GENERAL TEST REQUIREMENTS
4.1 General Monitoring Requirements
5 DETAILED REQUIREMENTS
5.1 Electical Tests
5.1.1 Output Characteristics
5.1.1.1 Amplitude
5.1.1.2 Rise and Fall Time
5.1.1.3 Zero Crossing Stability
5.1.1.4 Distortion, Overshoot and Ringing
5.1.1.5 Output Symmetry
5.1.1.6 Output Noise
5.1.1.7 Power On/Off Noise
5.1.2 Input Characteristics
5.1.2.1 Input Waveform Compatibility
5.1.2.1.1 Amplitude Variations
5.1.2.1.2 Input Impedance
5.2 Protocol Tests
5.2.1 RT Response to Command Words
5.2.1.1 RT Address
5.2.1.1.1 Valid RT Address
5.2.1.1.2 Invalid RT Address
5.2.1.2 Word Count
5.2.1.3 Subaddress
5.2.1.4 Error Injection
5.2.2 Optional Operation
5.2.2.1 Dual Redundant Operation
5.2.2.2 Mode Commands
5.2.2.2.1 Dynamic Bus Control
5.2.2.2.2 Synchronize
5.2.2.2.2.1 Synchronize (Without Data word)
5.2.2.2.2.2 Synchronize (With Data Word)
5.2.2.2.3 Transmit Status
5.2.2.2.4 Initiate Self Test
5.2.2.2.5 Transmit BIT Word
5.2.2.2.6 Transmitter Shutdown and Override
5.2.2.2.6.1 Dual Redundant Shutdown and Overrides
5.2.2.2.6.2 Selective Bus Shutdown and Overrides
5.2.2.2.7 Terminal Flag Bit Inhibit and Override
5.2.2.2.8 Reset Remote Terminal
5.2.2.2.9 Transmit Vector Word
5.2.2.2.10 Transmit Last Command
5.2.2.3 Status Word
5.2.2.3.1 Service Request
5.2.2.3.2 Broadcast
5.2.2.3.3 Busy
5.2.2.3.4 Subsystem Flag
5.2.2.3.5 Terminal Flag
5.2.2.4 Broadcast Messages
5.2.2.4.1 Response to Broadcast Messages
5.2.2.4.1.1 BC to RT Broadcast Commands
5.2.2.4.1.2 Broadcast Mode Commands
5.2.2.4.1.2.1 Broadcast Synchronize (Without Data Word)
5.2.2.4.1.2.2 Broadcast Synchronize (With Data Word)
5.2.2.4.1.2.3 Broadcast Initiate Self Test
5.2.2.4.1.2.4 Broadcast Transmitter Shutdown and Overrides
5.2.2.4.1.2.4.1 Broadcast Dual Redundant Shutdown and Overrides
5.2.2.4.1.2.4.2 Broadcast Selective Bus Shutdown and Overrides
5.2.2.4.1.2.5 Broadcast Terminal Flag Bit Inhibit and Override
5.2.2.4.1.2.6 Broadcast Reset Remote Terminal
5.2.2.4.1.3 RT to RT Broadcast Commands
5.2.2.5 RT to RT Transfers
5.2.2.5.1 RT to RT Transmit
5.2.2.5.2 RT to RT Receive
5.2.2.5.3 RT to RT Timeout
5.2.2.6 Illegal Commands
   
  TABLES
1 Error Formats
   
  FIGURES
1 General Test Configuration
2 Optional Test Configuration
3 Waveform Measurements
4 Zero Crossing Interval Measurements
5 Output Noise Configuration
6 RT-RT Timeout Measurement
A! Gap Time Measurement
   
  APPENDIX
A Test Plan Changes for MIL-STD-1553B, Notice 2 RTs

 

SAE document number AS4112 reprinted with permission © 1989 Society of Automotive Engineers, Inc.

1.0 Scope

  This test plan is broken into two major sections for the production testing of remote terminals:    Electrical and Protocol.

1.1 General

This production test plan defines the test requirements for verifying that Remote Terminals meet the requirements of MIL-STD-1553B, "Digital Time Division Command/Response Multiplex Data Bus."

1.2  Application

This is a general test plan for any remote terminal designed to meet the requirements of MIL-STD-1553B. These requirements shall apply to the remote terminal under test, when invoked in a specification or statement of work.

Tests specified may be performed in any order, combined with one another or combined with other tests of the subsystem in which the Remote Terminal may be embedded.

The Remote Terminal which is under test must also have its design validated per the  "Validation Test Plan for the Digital Time Divislon Command/Response Multiplex Data Bus Remote Terminals."

The tests specified are to be used in production test of a remote terminal chip, module or function within an equipment. It is intended that all stimuli and measurements be made via  external connections and/or test points. No required access to any other points is intended.
 
Special requirements such as those needed to meet armament bus requirements when specified in the individual equipment specification may, when within 1553B requirements, replace values or tolerances specified in this test plan for the purpose of generating a UUT production test procedure.

2.0 Applicable Documents

2.1  Standards, Military

MIL-STD-1553B, 21 Sep 1978, "Aircraft Internal Time Division Command/Response Multiplex Data Bus" with Notice 2, 8 September 1986.

2.2  Other Documents

MIL-HDBK-1553, Notice 1, 24 September 1986 "Validation Test Plan for  the Digital Time Division Command/Response Multiplex Data Bus Remote Terminals."

3.0 Definitions

  3.1  Responses

The following are definitions of the responses of the RT as used in this test plan.    In each case, the status word must have the correct terminal address and unused status bits    set to zero.

 3.1.1  BCR - Broadcast Command Received

The broadcast command received bit (bit time 15) is  set in status word.

 3.1.2 BUSY - Busy

The busy bit (bit time 16) is set in the status word.

3.1.3 CS - Clear Status

The status word may have the busy bit or service request bit set, or both. All other status code bits in the status word must be zero and the associated message must have the proper word count.

3.1.4  DBA - Dynamic Bus Acceptance

The dynamic bus control acceptance bit (bit time 18)  is set in the status word.

3.1.5  ME - Message Error

The message error bit (bit time 9) is set in the status word.

3.1.6  NR - No response

The addressed terminal does not produce any response to the command.

 3.1.7  Respond in Form

A terminal is said to "respond in form" if its response to an illegal command as defined in 4.4.3.4 of MIL-STD-1553B consists of a response formatted as though it were a legal command.

3.1.8  SF - Subsystem Flag

The subsystem flag bit (bit time 17) is set in the status word.

3.1.9  TF - Terminal Flag

The terminal flag bit (bit time 19) is set in the status word.

3.2  Other Definitions

3.2.1  UUT - Unit Under Test

3.2.2  RT - Remote Terminal

3.2.3  BC - Bus Controller

4.0 General Test Requirements

The following paragraphs define the configurations, pass/fail criteria, and general  procedures for testing remote terminals. Specifically, this document contains the test configurations and procedures for the Electrical Tests (5.1) and the Protocol Tests (5.2) for MIL-STD-1553B remote terminals. The remote terminal under test is referred to as the unit under test (UUT). Proper terminal responses are defined in each test paragraph.

4.1  General Monitoring Requirements

In addition to the specific tests that follow, certain RT  parameters must be continuously monitored throughout all tests. These parameters are:

  1. response time
  2. contiguous data
  3. proper Manchester encoding 
  4. proper bit count 
  5. odd parity
  6. proper word count
  7. proper terminal address in the status word
  8. reserved status and instrumentation bits in the status word are set to zero
  9. proper sync

The UUT shall have falled the test if at any time during the test any of these parameters fail to meet the requirements of MIL-STD-1553B.

5.0 Detailed Requirements

5.1 Electrical Tests

General Test Configuration

Figure 1. General Test Configuration

All tests shall use Fig. 1, General Test Configuration, with all measurements taken at point "A", unless otherwise noted. Each test paragraph contains the requirements for both transformer and direct coupled stubs. A UUT which provides both trans   former and direct coupled stubs must be tested on both stubs. Electrical tests shall be performed on all buses for UUTs with redundant bus configurations.

5.1.1 Output Characteristics

Optional Test Configuration

Figure 2. Optional Test Configuration

The following tests are designed to verify that all UUT output characteristics comply with MIL-STD-1553B. These tests shall be performed after establishing communications between the test equipment and the UUT.

If necessary, use the Optional Test Configuration, Fig. 2, ln order to isolate the UUT output from any reactive load presented by the Tester.

 5.1.1.1  Amplitude

Waveform Measurements

Figure 3. Waveform Measurements

A valid, legal transmit command shall be transmitted to the UUT, requesting the maximum number of words that it is capable of sending. The amplitude of the waveform transmitted by the UUT shall be measured, peak-to-peak, as shown in Fig. 3. The pass criteria for Vpp for transformer coupled stubs shall be 18.0 V minimum and 27.0 V maximum. The pass criteria for Vpp for direct coupled stubs shall be 6.0 V minimum and 9.0 V maximum.

 5.1.1.2  Rise and Fall Times

A valid, legal transmit command shall be sent to the UUT, requesting at least one data word. The rise and fall time of the UUT waveform shall be measured between the 10 and 90% points of the waveform as shown in Fig. 3. The measurements shall be taken at both the rising and falling edges of a sync waveform and a data bit waveform. The rise time (TR) and the fall time (TF) shall be measured. The pass criteria shall be 100 ns < = TR < =300 ns and 100 ns < = TF < = 300 ns.

Note: The rise time of the sync waveform shall be measured at the mid-crossing of a data word sync, and the fall time of the sync waveform shall be measured at the mid-crossing of the status word sync. The rise and fall times of the data bit waveform shall be measured at a zero crossing where the prior zero crossing and next zero crossing are at 500 ns intervals from the measured zero crossing.

5.1.1.3  Zero Crossing Stability

Zero Crossing Inverval Measurements

Figure 4. Zero Crossing Inverval Measurements

Selected valid legal transmit commands shall be sent to the UUT, requesting the UUT to transmit words having zero crossing time intervals of 500, 1000, 1500 and 2000 ns. The zero crossing time (Tzc) shall be measured for both positve to negative and the negative to positive waveforms as shown if Fig. 4. The pass criteria shall be that  Tzc = 500 + 25, 1000 ± 25, 1500 2000 ± 25 ns.

 5.1.1.4  Distortion

Overshoot and Ringing: A valid legal transmit command shall be sent to the UUT, requesting the UUT to transmit at least one data word. The distortion of the waveform, distortion voltage (VD), shall be measured as indicated in Fig. 3. Pass criterion shall be VD < = 900 mV, for transformer coupled stubs and VD < = 300 mV, for direct couple stubs.

 5.1.1.5  Output Symmetry

A valid legal transmit command shall be sent to the UUT requesting the maximum number of data words that the UUT is capable of transmitting. The output symmetry is determined by measuring the waveform tail-off at the end of each message. The maximum residual voltage (VR) shall be measured as shown in Fig. 3. The intermessage gap time shall be a minimum of 1 ms. The pass criterion shall be VR < = 250 mV peak for transformer coupled stubs and VR < = 90 mV peak for direct coupled stubs after time TT (the time beginning 2.5 µs after the mid-bit zero crossing of the last parity bit). This test shall  be run six times with each data word in the message having the same bit pattern.

The six data word patterns that shall be used are:

8000(HEX), 7FFF(HEX), 0000(HEX), FFFF(HEX), 5555(HEX), and AAAA(HEX)

Note: For terminals that cannot transmit data words, the output symmetry test shall be  performed on the status word response to a receive command or mode command.

 5.1.1.6  Output Noise

Output Noise Configuration

Figure 5. Output Noise Configuration

The test configuration shown in Fig. 5 shall be used to test the UUT inactive bus output noise levels. The test shall be conducted while the UUT is in the power-on receive state. The output noise (Vrms) shall be measured at point "A" as shown in Fig. 5. Measurements shall be made with an instrument that has a minimum Frequency bandwidth of from DC to 10 MHz. The pass criterion shall Vrms < = 14 mV for transformer coupled stubs and Vrms < = 5.O mV for direct coupled stubs.

5.1.1.7  Power On/Off Noise

A UUT shall not emit any spurious differential output during a power-up or power-down sequence. Power shall be applied to the UUT and any outputs from the UUT to the bus shall be measured. Power shall be removed from the UUT and any output to the bus from the UUT shall be measured.

The pass criterion shall be:

  1. For transformer coupled stubs, any spurious noise pulses produced shall be less than ±250 mV peak.
  2. For direct coupled stubs, any spurious noise pulses produced shall be less than ±90 mV peak.

NOTE: Use normal on/off power sequence of UUT.

5.1.2 Input Characteristics

5.1.2  Input Characteristics

The input tests are designed to verify that multiplex devices can properly decode bi-phase data.

 5.1.2.1  Input Waveform Compatibility

 5.1.2.1.1  Amplitude Variations

A sequence of valid legal receive commands shall be transmitted to the UUT. The test shall be performed for input voltage levels of 0.20, 0.86, and 6.0 Vpp for transformer coupled stubs, and at 0.28, 1.2, and 9.0 Vpp for direct coupled stubs. A minimum of 1000 commands shall be transmitted to the UUT at each input level. The response of the UUT shall be monitored for every message at each input level.

The pass criteria shall be:

  1. NR for transformer coupled stub inputs of 0.20 Vpp.
  2. CS for transformer coupled stub inputs of 0.86 Vpp. 
  3. CS for transformer coupled stub inputs of 6.0 Vpp.
  4. NR for direct coupled stub inputs of 0.28 Vpp.
  5. CS for direct coupled stub inputs of 1.2 Vpp. 
  6. CS for direct coupled stub inputs of 9.0 Vpp.

 5.1.2.1.2  Input Impedance

The input impedance of the UUT shall be measured first with the power on and repeated with the UUT power off. The input impedance, Zin, shall be measured with a sinusoidal waveform having an amplitude 1.0 to 2.0 Vrms, at a frequency of 1.0 MHz. The pass criterion shall be Zin > = 1000 ? for transformer coupled stubs and Zin > = 2000 ? for direct coupled stubs.

For this test, do not use Fig. 1; remove all loads from UUT.

5.2 Protocol Tests

All tests in this section shall use the test configuration shown in Fig. 1. The test signal amplitude shall be 3.0 Vpp for direct coupled stubs and 2.1 Vpp for transformer coupled stubs measured at point A. For UUTs having both direct and transformer coupled stubs, the protocol tests need only be performed on one stub type per bus. Any condition, which causes the UUT to respond other than as called out in MIL-STD-1553B, to lock up or require a power cycle in order to recover from a failure, shall automatically cause that UUT to fail the test. The protocol tests shall be performed on all buses for UUTs with redundant bus configurations.

5.2.1 RT Response to Command Words

5.2.1.1  RT Address

The purpose of this test is to verify that the UUT responds only to valid legal commands, that is, those that contain the address of the UUT.

5.2.1.1.1  Valid RT Address

The test equipment shall transmit to the UUT one valid legal transmit command and one valid legal receive command with the minimum word count for the UUT. Associated data may be random or controlled depending on UUT requirements. The pass criteria shall be that the UUT responds with CS for each command. If the UUT has variable address capability, this test shall be repeated for the following addresses:

 00001, 00010, 00100, 01000, 10000, 00000

5.2.1.1.2  Invalid RT Address

The test equipment shall transmit to the UUT receive commands and transmit commands using all RT addresses not assigned to the UUT (with the exception of address 11111). Subaddress and word count fields shall be identical to those used in 5.2.1.1.1. The pass criteria shall be NR for each command.

5.2.1.2  Word Count

The purpose of the test is to verify that the UUT responds properly to all word counts implemented. During the test, the test equipment will transmit one valid, legal, non-mode transmit command and one valid, legal, non-mode receive command for each implemented word count. Only one subaddress is needed for any word count. The pass criteria shall be CS for each command.

5.2.1.3  Subaddress

The purpose of this test is to verify that the UUT responds properly to all subaddresses implemented. During this test, the test equipment shall transmit one valid, legal, non-mode transmit command and one valid, legal, non-mode receive command for each implemented subaddress. Only one word GOunt is needed for any subaddress. The pass criteria shall be CS for each command.

5.2.1.4  Error Injection

These tests are intended to examine the UUT response when specific errors are forced into the message stream. The UUT shall not respond with a status word. If the data words it decodes fail any of the validity tests, the UUT should internally set the message error bit in its status word buffer. If the command word it decodes fails any of the validity tests, it shall ignore the command and wait for the next command (the ME bit should not be internally set in this case). For this test, valid legal commands will be sent to the UUT for Steps 1 and 3 in the test sequence below. Each error condition listed in Table 1 shall be injected in Step 2 of the test sequence. One error per test sequence shall be implemented.

  1. Transmit a valid, legal command to the UUT.
  2. Transmit to the UUT a message which contains one of the error conditions listed in Table 1.
  3. Transmit a valid, legal command to the UUT.

 The pass criteria shall be:

  1.  The UUT shall respond with CS for Steps 1 and 3 in the test sequence above. 
  2.  The UUT shall not respond to commands for Step 2 in the test sequence above.
Table 1 - Error Formats
ERROR TYPE LOCATION
Parity Receive Command Word
Parity Transmit Command Word
Parity Data Word
Bit Count (-1bit) Receive Command Word
Bit Count (+2 bits) Receive Command Word
Bit Count (-1 bit) Transmit Command Word
Bit Count (+2 bits) Between Two Data Words
Bit Count (-1 bit) Between Two Data Words
Bi-phase (high) Ripple Through Transmit Command
Bi-phase (high) Ripple Through Receive Command
Bi-phase (low) Ripple Through Transmit Command
Bi-phase (low) Ripple Through Receive Command
Bi-phase (low) Ripple Through Data Word
Bi-phase (high) Ripple Through Data Word
Sync Command Word, Patterns:
111100
110000
111001
011000
000111
Sync Data Word, Patterns:
000011
001111
000110
100111
111000
Contiguous Data Between Command and Data Words
Contiguous Data Between Two Data Words
Message Length (+) Receive Message Plus One Data Word
Message Length (-) Receive Message Minus One Data Word
Message Length (+) Transmit Command Plus Data Word
NOTE: For contiguous data errors, receive commands shall be used and the contiguous data error shall be 4.0 µs as measured from the mid-bit zero crossing of the parity bit of the preceding word to the mid-sync zero crossing of the following word.

5.2.2 Optional Operation

This section provides for testing the optional requirements of MIL-STD-1553B. If a remote terminal implements any of the options, it shall be tested in accordance with the test identified for the option.

5.2.2.1 Dual Redundant Operation

This test shall be performed only if the UUT is configured with dual redundant buses. The requirements are as follows:

  1. The UUT is required to accept a valid command received on the alternate bus while responding to a command on the original bus.
  2. The UUT is required to respond to the valid command occurring later in time when overlapping valid commands are received on both buses.
  3. When Step 1 or 2 occurs, the UUT shall reset and respond to the new command on the alternate bus.

 Legal messages shall be used in this test. The following test sequence shall be performed twice for each interrupting command, once for each redundant bus:

  Step 1.  Send a valid command to the UUT requesting the maximum number of data words that the UUT is designed to transmit.
  Step 2.  Send the interrupting command on the alternate bus beginning no sooner than 4.0 µs after the beginning of the first command.
  Step 3.  Send a valid "Transmit Status" mode command on the first bus after the messages on both buses have been completed. (If "Transmit Status" is not used, delete this step.)

  The pass criteria shall be:

Step 1.  NR, truncated message or CS
Step 2.  CS
Step 3.  CS if transmit status is implemented.

5.2.2.2 Mode Commands

The purpose of these tests is to verify that the UUT responds properly to implemented mode commands. The tests are not intended to verify the mission aspects stated in the equipment specification. The UUT shall be tested for each mode code implemented with a subaddress field mode code indicator of all zeros and repeated with a subaddress field of all ones. The pass criteria are defined in each test paragraph.
 

5.2.2.2.1  Dynamic Bus Control

The purpose of this test is to verify that the UUT has the ability to recognize the "Dynamic Bus Control" mode command and to take control of the data bus. A valid legal dynamic bus control mode command shall be sent to the UUT. The pass criteria shall be that the UUT responds with a DBA upon acceptance of bus control or a CS upon rejection of bus control. The UUT shall take control of the data bus when its response is DBA as required in the UUT's design specification.

5.2.2.2.2 5 Synchronize

The following paragraphs provide the test criteria for the "Synchronize"  mode commands:

 5.2.2.2.2.1  Synchronize (Without Data Word)

The purpose of this test is to verify that the UUT has the ability to recognize a "Synchronize" mode command without a data word. A valid legal "Synchronize" (without data word) mode command shall be sent to the UUT. The pass criterion shall be that the UUT responds with CS.

5.2.2.2.2.2  Synchronize (With Data Word)

The purpose of this test is to verify that the UUT has the ability to recognize a "Synchronize" mode command with a data word. A valid legal "Synchronize" (with data word) mode command shall be sent to the UUT. The pass criterion shall be that the UUT responds with CS.

5.2.2.2.3  Transmit Status

The purpose of this test is to verify that the UUT has the ability to recognize the "Transmit Status" mode command and respond with its last status word.  The following sequence shall be performed:

  Step 1.  A valid legal message shall be sent to the UUT.
  Step 2.  A legal receive command with a parity error in a data word shall be sent to the UUT.
  Step 3.  A valid legal "Transmit Status" mode command shall be sent to the UUT.
  Step 4.  Repeat Step 3.
  Step 5.  A valid legal receive command shall be sent to the UUT.

The pass criteria for the above steps shall be as follows:

 Step 1. CS
 Step 2. NR
 Step 3. ME
 Step 4. ME
 Step 5. CS.

5.2.2.2.4 Initiate Self-Test

The purpose of this test is to verify that the UUT has the ability to recognize the "Initiate Self-Test" mode command. A valid legal "Initiate Self-Test" mode command shall be sent to the UUT. The pass criterion shall be that the UUT responds with CS.

Note: Normal UUT operation may be affected during the Self-Test execution time. Detailed requirements shall be as defined by the UUT's design specification.

5.2.2.2.5  Transmit BIT Word

The purpose of this test is to verify that the UUT has the ability to recognize the "Transmit BIT Word" mode command. A valid legal "Transmit BIT Word"  mode command shall be sent to the UUT. The pass criterion shall be that the UUT responds with a CS followed by a valid data word.

5.2.2.2.6  Transmitter Shutdown and Override

The purpose of this test is to verify that the UUT  has the ability to recognize the "Transmitter Shutdown" and "Override Transmitter shutdown" mode commands. The pass criterion for each individual test is contained in one of the paragraphs below. To test all bus combinations, in this sequence each bus in turn shall be identified as the primary bus. All other buses shall be tested in turn as the selected alternate bus using Steps 1 through 10.
  

  Step 1.  A valid legal command shall be sent on the primary bus to the UUT. A CS response shall be verified.
  Step 2.  A valid legal command shall be sent on the selected alternate bus to the UUT. A CS response shall be verified.
  Step 3.  A valid legal mode command to shut down the transmitter shall be sent to the UUT on the primary bus. A CS response shall be verified.
  Step 4.  A valid legal command shall be sent on the selected alternate bus to the UUT. A NR shall be verified.
  Step 5.  A valid legal command shall be sent on the primary bus to the UUT.  A CS response shall be verified.
  Step 6.  A valid legal mode command to override the transmitter shutdown shall be sent to the UUT on the selected alternate bus. A NR shall be verified.
  Step 7.  A valid legal command shall be sent to the UUT on the selected alternate bus. A NR shall be verified.  
  Step 8.  A valid legal mode command to override transmitter shutdown shall be sent to the UUT on the primary bus. A CS shall be verified.
  Step 9.  A valid legal command shall be sent on the selected alternate bus to the UUT. A CS shall be verified.
  Step 10. A valid legal command shall be sent on the primary bus to the UUT.  A CS shall be verified.

5.2.2.2.6.1  Dual Redundant Shutdowns and Overrides

This test shall verify that the UUT recognizes the dual redundant mode commands to shut down the alternate bus transmitter and to override the shutdown.

A valid legal "Transmitter Shutdown" mode command shall be encoded into the command word to cause an alternate bus transmitter shutdown. A valid legal "Override Transmitter Shutdown" mode command shall be encoded into the command word to cause an override of the transmitter shutdown. The test sequence in 5.2.2.2.6 shall be used for each case including verification of the UUT response indicated. The pass criterion shall be that the UUT performs as defined in each step.

5.2.2.2.6.2  Selective Bus Shutdowns and Overrides

This test shall verify that the UUT recognizes the multi-redundant mode commands to shut down a selected bus transmitter and to override the shutdown. A valid legal "Selected Transmitter Shutdown" receive mode command shall be encoded, accompanied by the appropriate data word, to cause a selective bus transmitter shutdown. A valid legal "Override Selected Transmitter Shutdown" receive mode command shall be encoded accompanied by the appropriate data word to cause an override of the selected bus transmitter shutdown. The test sequence in 5.2.2.2.6 shall be used for each case including verification of the UUT response indicated. The pass criteria shall be that the UUT performs as defined in each step.

5.2.2.2.7  Terminal Flag Bit Inhibit and Override

This test verifies that the UUT recognizes and responds properly to the mode commands of "Inhibit Terminal Flag Bit" and "Override Inhibit Terminal Flag Bit." Beginning in Step 2 of the test sequence below, the UUT shall be caused to set the terminal flag bit.

  Step 1.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a CS response verified.
  Step 2.  Introduce a condition that will set the terminal flag in the UUT status response. Send a valid legal receive command with at least one data word to the UUT and verify that    the TF bit  is set in the returned status word.
  Step 3.  A valid legal "Inhibit Terminal Flag" mode command shall be transmitted to the UUT and a CS or TF response verified.
  Step 4.  Repeat Step 1 and verify a CS response.
  Step 5.  A valid legal "Override Inhibit Terminal Flag" mode command shall be transmitted to the UUT and a CS or TF verified in the returned status word.
  Step 6.  A valid legal receive command with at least one data word shall be transmitted and a TF verified in the returned status word.
  Step 7. Procedures, as defined for the UUT, shall be performed which reset the TF bit.
  Step 8.  Repeat Step 1.

The pass criterion shall be that the UUT performs as defined in each step.

5.2.2.2.8  Reset Remote Terminal

This test shall verify that the UUT has the capability to recognize the mode command to reset itself to a power up initialized state. For this test, a reset mode command shall be transmitted to the UUT and a CS response verified.

Note: Normal UUT operation may be affected during the reset execution time. Detailed requirements shall be as defined by the UUT's design specification.

5.2.2.2.9  Transmit Vector Word

This test verifies the capability of the UUT to recognize and respond properly to a "Transmit Vector Word" mode command. A valid legal "Transmit Vector Word" mode command shall be transmitted to the UUT and a CS response shall be verified.

5.2.2.2.10  Transmit Last Command

This test verifies that the UUT recognizes and responds properly to a "Transmit Last Command" mode command. The following test sequence shall be used:

  Step 1.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a CS response verified.
  Step 2.  A valid legal receive command, different from that used in Step 1 above with at least one data word, shall be transmitted to the UUT and a parity error shall be  encoded into the first data word. A NR shall be the proper UUT action.
  Step 3.  A valid legal "Transmit Last Command" mode command shall be transmitted to the UUT and a status response of ME followed by a data word containing the last command (command word from Step 2) shall be verified.
  Step 4.  A valid legal "Transmit Status" mode command shall be transmitted to the UUT and a status response with a ME set shall be verified.
  Step 5.  A valid legal "Transmit Last Command" mode command shall be transmitted to the UUT and a status response of ME followed by a data word containing the last command (command word from Step 4) shall be verified.
  Step 6.  A valid legal "Transmit Last Command" mode command shall be transmitted to the UUT and a status response of ME followed by a data word containing the  last command (command word from Step 4) shall be verified.
  Step 7.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a CS response verified.
  Step 8.  A valid legal "Transmit Last Command" mode command shall be transmitted to  the UUT and a status response of CS followed by a data word containing the last command (command word from Step 7) shall be verified.

5.2.2.3 Status Word

The following tests verify that all implemented status word bits are properly used and cleared. The UUT has failed a test sequence if it does not respond as indicated in each test paragraph for any implemented status word bit.

5.2.2.3.1  Service Request

This test verifies that the UUT sets the service request bit as necessary and clears it when appropriate. The UUT shall set bit time 11 of the status word when a condition in the UUT warrants the RT to be serviced. A reset of the bit shall occur as defined by each RT. The following steps shall be performed and the appropriate responses verified:

  Step 1.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a CS response with the service request bit reset verified.
  Step 2.  A condition, which causes the service request bit to be set shall be introduced into the UUT. A valid legal receive command with at least one data word shall be transmitted to the UUT and a status response having the service request  bit set shall be verified.
  Step 3.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a status response having the service request bit set shall be verified.
  Step 4.  Procedures, as defined for the UUT, shall be performed which reset the service request bit. A valid legal receive command with at least one data word shall be transmitted to the UUT and a CS response with the service request bit reset shall be verified.

The pass criterion for this test shall be the successful completion of Steps l through 4.

5.2.2.3.2  Broadcast

This test verifies that the UUT sets the broadcast command received bit of the status word after receiving a broadcast command. The UUT shall set status bit 15  to a logic one after receiving the broadcast command. The following test sequence shall be performed using either the "Transmit Last Command" or "Transmit Status" mode command to verify the bit condition.

  Step 1.  A valid legal broadcast receive message shall be transmitted to the UUT.  A NR shall be verified.
  Step 2.  A valid legal "Transmit Last Command" or "Transmit Status" mode command shall be transmitted to the UUT. In either case, verify BCR. If the "Transmit Last Command" mode command is used, the data word containing the  broadcast command shall be verified.
  Step 3.  A valid, legal, non-broadcast command shall be transmitted to the UUT and a status word with the broadcast command received bit reset shall be verified.
  Step 4.  A broadcast receive message with a parity error in one of the data words shall be transmitted to the UUT. A NR shall be verified.
  Step 5.  A valid legal "Transmit Last Command" or "Transmit Status" mode command shall be transmitted to the UUT. In either case, a status word with the message error bit set shall be verified. (BCR may be set.) If the "Transmit Last Command" mode command is used, the data word containing the broadcast command shall be verified.

The pass criterion for this test shall be the successful completion of Steps 1 through 5.

5.2.2.3.3  Busy

This test verifies the capability of the UUT to set the busy bit of the status word. Bit time 16 of the status word shall be set when the UUT is busy.

  Step 1.  Procedures as defined for the UUT shall be performed which set the busy bit.
  Step 2.  A valid legal transmit command shall be transmitted to the UUT and only a status word response with the busy bit set shall be verified. The UUT shall not transmit the requested data words when the busy bit is set.
  Step 3.  Procedures, as defined for the UUT, shall be performed which reset the busy bit.
  Step 4.  A valid legal transmit command shall be transmitted to the UUT and a status word with the busy bit reset shall be verified. The UUT shall have responded with the correct number of data words.
  Step 5.  Repeat Step 1.
  Step 6.  A valid legal receive command shall be transmitted to the UUT and a status word response with the busy bit set shall be verified.
  Step 7.  Repeat Step 3.
  Step 8.  A valid legal receive command shall be transmitted to the UUT and a status word response with the busy bit reset shall be verified.

The pass criterion for this test shall be the successful completion of Steps 1 through 8.

5.2.2.3.4  Subsystem Flag

This test verifies the capability of the UUT to set the subsystem flag bit of the status word. Bit time 17 of the status word shall be set to a logic one when a subsystem fault has been determined. Prior to performing the test sequence below, a condition. which sets the subsystem flag bit, must be activated.

  Step 1.  A valid legal transmit command shall be transmitted to the UUT and a status response having the subsystem flag bit set shall be verified.
  Step 2.  Procedures, as defined for the UUT, shall be performed which reset the subsystem flag bit.
  Step 3.  A valid legal transmit command shall be transmitted to the UUT and a status word with the subsystem flag bit reset shall be verified.

The pass criterion for this test shall be the successful completion of Steps 1 through 3.

5.2.2.3.5  Terminal Flag

This test verifies that the UUT sets the terminal flag bit as necessary and clears it when appropriate. The UUT shall set bit time 19 of the status word when an occurrence in the UUT causes a terminal fault condition. Prior to performing the test sequence below, a condition which sets the terminal flag bit must be activated.

  Step 1.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a status response with the TF bit set shall be verified.
  Step 2.  Procedures, as defined for the UUT, shall be performed which reset the TF bit.
  Step 3.  A valid legal transmit command shall be transmitted to the UUT and a status word with the TF bit reset shall be verified.

The pass criterion for this test shall be the successful completion of Steps 1 through 3.

5.2.2.4 Broadcast Messages

The following tests verify that the UUT responds properly to broadcast messages.

Note: In the following test sequences, a "Transmit Last Command" mode command shall be used to verify the reception of the broadcast message by the UUT. If the "Transmit Last Command" mode command is not implemented, the "Transmit Status" mode command shall be used. If neither mode command is implemented, this test will not be performed.

5.2.2.4.1  Response to Broadcast Commands

The purpose of this test is to verify that the UUT responds properly to broadcast commands. The commands are classified into three categories. BC to RT broadcast commands broadcast mode commands, and RT to RT broadcast commands. Each category is tested separately in the following paragraphs. Use the following test sequence unless otherwise noted:

  Step 1.  A valid legal receive message shall be sent to the UUT.
  Step 2.  A valid legal broadcast message shall be sent to the UUT.  
  Step 3.  A "Transmit Last Command" mode command shall be sent to the UUT.

5.2.2.4.1.1  BC to RT Broadcast Commands

All possible broadcast commands meeting the criteria of 4.4.1.1 of MIL-STD-1553B except broadcast mode commands shall be sent to the UUT. Each command word shall be followed by the proper number of contiguous valid data words.

The pass criteria are as follows:

 Step 1. CS
 Step 2. NR
 Step 3. BCR and the data word contains the broadcast command sent in Step 2.

5.2.2.4.1.2  Broadcast Mode Commands

The purpose of this test is to verify that the UUT responds properly to implemented broadcast mode commands. This test is not intended to verify the mission aspects stated in the equipment specification. The UUT shall be tested for each mode code implemented with a subaddress field mode code indicator of all zeros and repeated with a subaddress field of all ones. The pass criteria are defined in each test paragraph.

5.2.2.4.1.2.1 Broadcast Synchronize (Without Data Word)

The purpose of this test is to verify that the UUT has the ability to recognize a broadcast "Synchronize" (without data word) mode command. The test sequence defined in 5.2.2.4.1 shall be used with a broadcast "Synchronize" (without data word) mode command in Step 2. The pass criteria for the above steps shall be as follows:

  Step 1.CS
  Step 2. NR
  Step 3. BCR and the data word contains the broadcast command sent in Step 2.

5.2.2.4.1.2.2  Broadcast Synchronize (With Data Word) 

The purpose of this test is to verify that the UUT has the ability to recognize a broadcast "Synchronize" (with data word) mode command. The test sequence defined in 5.2.2.4.1 shall be used with a broadcast "Synchronize" (with data word) mode command in Step 2. The pass criteria for the above steps shall be as follows:

  Step 1. CS
  Step 2. NR
  Step 3. BCR and the data word contains the broadcast command sent in Step 2.

5.2.2.4.1.2.3  Broadcast Initiate Self-Test

The purpose of this test is to verify that the UUT has the ability to recognize the broadcast "Initiate Self-Test'' mode command. The test sequence defined in 5.2.2.4.1 shall be used with a broadcast "Initiate Self-Test" mode command in Step 2. The pass criterion for each of the above steps shall be as follows:

 Step 1. CS
 Step 2. NR
 Step 3. BCR and the data word contains the broadcast command sent in Step 2.

Note: Normal UUT operation may be affected during the Self-Test execution time. Detailed requirements shall be as defined by the UUT's design specification.

 5.2.2.4.1.2.4  Broadcast Transmitter Shutdown and Overrides

The purpose of this test is to verify that the UUT has the ability to recognize and properly execute these broadcast mode commands. The pass criterion for each individual test is contained in one of the paragraphs below. The following sequence shall be performed for each test:

  Step 1.  A valid legal command shall be sent on the primary bus to the UUT. A CS response shall be verified.
  Step 2.  A valid legal command shall be sent on the selected alternate bus to the UUT. A CS response shall be verified.
  Step 3.  A valid legal "Broadcast Transmitter Shutdown" mode command shall be sent to the UUT on the primary bus. A NR response shall be verified.
  Step 4.  A "Transmit Last Command" mode command shall be sent on the primary bus to the UUT. A BCR response shall be verified, followed by the data word transmitted in Step 3.
  Step 5.  A valid legal command shall be sent on the selected alternate bus to the UUT. A NR shall be verified.
  Step 6.  A valid legal command shall be sent on the primary bus to the UUT. A CS response shall be verified.
  Step 7.  A valid legal broadcast "Override Transmitter Shutdown" mode command shall be sent to the UUT on the selected alternate bus. A NR shall be verified.
  Step 8.  A valid legal command shall be sent to the UUT on the selected alternate bus. A NR shall be verified.
  Step 9.  A valid legal broadcast "Override Transmitter Shutdown" mode command shall be sent to the UUT on the primary bus. A NR shall be verified.
  Step 10.  A "Transmit Last Command" mode command shall be sent on the primary bus to the UUT. A BCR response shall be verified, followed by the data word from Step 9.
  Step 11.  A valid legal command shall be sent on the selected alternate bus to the UUT.  A CS shall be verified.
  Step 12. A valid legal command shall be sent on the primary bus to the UUT. A CS shall be verified.

5.2.2.4.1.2.4.1 Broadcast Dual Redundant Shutdowns and Overrides

This test shall verify that the UUT recognizes the dual redundant broadcast mode commands to shut down the alternate bus transmitter and to override the shutdown. In a dual redundant system, each bus must be tested as the alternate bus and as the primary bus. A valid legal broadcast "Transmitter Shutdown" mode command shall be used in Step 3. A valid legal broadcast "Override Transmitter Shutdown" mode command shall be used in Steps 7 and 9. The test sequence in 5.2.2.4.1.2.4 shall be used for each case, including verification of the UUT response indicated. The pass criteria shall be that the UUT performs as defined in each step.

5.2.2.4.1.2.4.2  Broadcast Selective bus Shutdowns and Overrides

This test shall verify that the UUT recognizes the multi-redundant broadcast mode commands to shut down a selected bus transmitter and to override the shutdown. In a multi-redundant system, each bus must be tested as the alternate bus and each as the primary bus. A valid legal broadcast "Selected Transmitter Shutdown" mode code shall be encoded accompanied by the appropriate data word in Step 3 to cause a selective bus transmitter shutdown. A valid legal broadcast "Override Selected Transmitter Shutdown" mode shall be encoded accompanied by the appropriate data word in Steps 7 and 9 to cause an override of the selected bus transmitter shutdown. The test sequence in 5.2.2.4.1.2.4 with the changes given shall be performed using each bus as the primary bus and each as the alternate bus, including verification of the UUT response indicated. The pass criteria shall be that the UUT performs as defined in each step.

5.2.2.4.1.2.5  Broadcast Terminal Flag Bit Inhibit and Override

This test verifies that the UUT recognizes and responds properly to the broadcast mode commands of "Inhibit Terminal Flag Bit" and "Override Inhibit Terminal Flag Bit". Beginning in Step 2 of the test sequence below, the UUT shall be caused to set the terminal flag bit.

  Step 1.  A valid legal receive command with at least one data word shall be transmitted to the UUT and a CS response verified.
  Step 2.  Introduce a condition that will set the terminal flag in the UUT status response.  Send a valid legal receive command with at least one data word to the UUT and verify that the TF bit is set in the returned status word.
  Step 3.  A valid legal "Inhibit Terminal Flag" broadcast mode command shall be transmitted to the UUT and a NR verified.
  Step 4.  A "Transmit Last Command" mode command shall be sent to the UUT. A BCR response shall be verified, followed by the data word from Step 3.
  Step 5.  Repeat Step 1 and verify a CS response.
  Step 6.  A valid legal "Override Inhibit Terminal Flag" broadcast mode command shall be transmitted to the UUT and a NR verified.
  Step 7.  A "Transmit Last Command" mode command shall be sent to the UUT. A BCR shall be verified.
  Step 8.  A valid legal receive command with at least one data word shall be transmitted and a TF verified in the returned status word.
  Step 9.  Procedures, as defined for the UUT, shall be performed which reset the TF bit.
  Step 10. Repeat Step 1.

The pass criteria shall be that the UUT performs as defined in each step.

5.2.2.4.1.2.6  Broadcast Reset Remote Terminal

This test shall verify that the UUT has the capability to recognize the broadcast mode command to reset itself to a power-up initialized state. For this test, the sequence in 5.2.2.4.1 shall be used with a broadcast "Reset Remote Terminal" mode command in Step 2.

Note: Normal UUT operation may be affected during the Reset execution time. Detailed requirements shall be as defined by the UUT's design specification.

The pass criteria shall be as follows:

Step 1. CS
Step 2. NR
Step 3. action and response defined by UUT's design specifications

5.2.2.4.1.3  RT to RT Broadcast Commands

The purpose of this test is to verify that the UUT responds properly to broadcast RT to RT commands with the UUT as the receiving RT. The following test sequence shall be used:

  Step 1.  A valid legal receive message shall be sent to the UUT.
  Step 2.  A valid legal broadcast RT to RT command pair shall be sent to the UUT.
  Step 3.  A "Transmit Last Command" mode command shall be sent to the UUT.
  Step 4.  Repeat Step 1.

The pass criteria shall be as follows:

 Step 1. CS
 Step 2. NR from the UUT
 Step 3.  BCR and the data word contains the receive command of the RT to RT command word pair of Step 2
 Step 4. CS

5.2.2.5 RT to RT Transfers

This test is intended to verify proper UUT operation during RT to RT transfers. For this test, the bus tester shall act as the bus controller and receiving or transmitting remote terminal, as required.

5.2.2.5.1  RT to RT Transmit

A valid legal RT to RT command pair shall be sent to the UUT. The transmit command shall be addressed to the UUT. The pass criterion shall be CS.

5.2.2.5.2  RT to RT Receive

A valid legal RT to RT command pair followed in 4 to 12 ps by a valid status word with the RT address of the transmit command and the proper number of data words shall be sent to the UUT. CS shall be verified.

5.2.2.5.3  RT to RT Timeout
RT-RT Timeout Measurement

Figure 6. RT-RT Timeout Measurement

The purpose of this test is to verify that the UUT functions properly when operating as the receiving RT in an RT to RT transfer. The UUT must not respond after receiving an RT to RT command pair if the data is not received within 54 to 60 µs as shown in Fig. 6. This time is measured from the zero crossing of the parity bit of the receive command to the mid sync zero crossing of the first data word. The following test sequence shall be performed:

  Step 1.  A valid legal RT-to-RT command pair followed in 4 to 12 ps by a valid status word with the RT address of the transmit command and the proper number of  data words shall be sent to the UUT. CS shall be verified.
  Step 2.  The time between the command pair and status word of Step 1 shall be increased until the UUT (receiving RT) stops responding and the time "T" as specified in Fig. 6 shall be measured. This time shall be between 54 and 60 ps.

The pass criterion for this test shall be the successful completion of Steps 1 and 2.

5.2.2.6 Illegal Commands

This test shall be performed if the UUT has the illegal command detection option implemented. If this test is performed, the Word Count (5.2.1.2) and Subaddress (5.2.1.3) tests shall not be performed. The requirements are as follows:

With the UUT terminal address set for a specific code and all commands issued containing that code, perform the following tests:

  Step 1.  Send a valid command to the UUT with subaddress 00001, T/R bit 0, and word count 00000, and appropriate number of data words.
  Step 2.  Send any valid legal receive command with appropriate data word(s) to the UUT.
  Step 3.  Repeat Step 1 for all other combinations of subaddress (except 00000 and 11111),  T/R and word counts with appropriate data words following for receive commands.
  Step 4.  Repeat Step 2 following each of the commands of Step 3.
  Step 5.  Send a valid illegal receive command to the UUT with a parity error in one of  the data  words.
  Step 6.  Send a "Transmit Status" mode command to the UUT. If "Transmit Status" is not implemented, proceed to Step 7.
  Step 7.  Repeat Step 2.
  Step 8.  Send an illegal command to the UUT with a parity error in the command word.
  Step 9.  Send a "Transmit Last Command'' mode command to the UUT. If "Transmit Last Command'' is not implemented, proceed to Step 10.
  Step 10. Repeat Step 2.
  Step 11. Repeat Step 1 for all combinations of T/R and mode code for subaddresses, 00000 and 11111 (mode commands) with a valid data word contiguously following each receive command.
  Step 12. Repeat Step 2 following each of the commands of Step 3.

The pass criteria shall be:

  Step 1. CS for legal commands and status word only with ME set for illegal commands
  Step 2. CS
  Step 3. CS for legal commands and status word only with  ME set for illegal commands
  Step 4. CS
  Step 5. NR
  Step 6. ME
  Step 7. CS
  Step 8. NR
  Step 9. CS and a data word containing the command word associated with Step 7
  Step 10. CS
  Step 11. status word only with ME bit set for unimplemented mode commands; for undefined mode commands, status word only with ME bit set, or NR if UUT does not respond to undefined mode commands
 Step 12. CS  

Appendix A

TEST PLAN CHANGES FOR MIL-STD-1553B, NOTICE 2 RTs

For remote terminals destgned to comply with MIL-STD-1553B Notice 2, the following changes shall be made for tests or pass criteria, or both, in this document:

A1.  Unique Address

The purpose of this test is to verify that the UUT can be assigned a unique address from an external connector on the UUT. The following shall be performed for the UUT:

  Step 1.  Send a valid legal command to the UUT.
  Step 2.  After externally changing the RT address to simulate a single point address validation failure (for example, parity error on the address lines), repeat Step 1.

Note: Power cycling may be required after externally changing the RT address.

The pass criteria shall be:

  Step 1. CS
  Step 2. NR

A2.  Mode Codes

Compliance with the following paragraphs is no longer optional:

5.2.2.2.3  Transmit Status
5.2.2.2.6  Transmitter Shutdown and Override
5.2.2.2.8  Reset Remote Terminal

A3.  Reset Remote Terminal

Gap Time Measurement

Figure A-1. Gap Time Measurement

The purpose of this test is to verify that the UUT has the ability to recognize the reset terminal mode command and the UUT to complete the reset function within its design time. The following sequence shall be performed once with time T =  Tdr and again with time T = Tdr (see Step 2) where Tdr is the actual maximum design value for reset time. In no case shall T be greater than 5 ms.

  Step 1. A reset remote terminal mode command shall be sent to the UUT on one bus.
  Step 2.  After time T from Step 1, as measured per Fig. A-1, a valid legal command shall be sent to the UUT on the same bus.
  Step 3. A valid legal transmitter shutdown mode command shall be sent to the UUT on the same bus.
  Step 4.  A valid legal command shall be sent to UUT on the alternate bus.
  Step 5.  A reset remote terminal mode command shall be sent to the UUT on the first bus.
  Step 6.  After time T, repeat Step 4.

The pass criteria for each of the above steps shall be as follows:

  Step 1. CS
  Step 2. CS (with BUSY bit reset) for time T = Tdr, and CS, CS with BUSY bit or NR (whichever is the design requirement) for T < Tdr
  Step 3. CS
  Step 4. NR
  Step 5. CS
  Step 6. CS

A4.  Initiate Self-Test

The purpose of this test is to verify that the UTT has the ability to recognize the initiate self-test mode command and complete self test within its design time. The following sequence shall be performed once with time T > Tdt and again with the time T < Tdt (see Step 2) where Tdt is the actual maximum design value for self test time. In no case shall T be greater than 100 ms.

  Step 1.  An initiate self-test mode command shall be sent to the UUT on one bus.
  Step 2.  After time T from Step 1, as measured per Fig. A-1, a valid legal command shall be sent to the UUT on the same bus. The test shall be performed with T set to a value determined by actual design requirement.

The pass criteria for each of the above steps shall be as follows:

  Step 1. CS
  Step 2. CS (with BUSY bit reset) for all time T > the time used in Step 2, and CS, CS with BUSY bit set or NR (whichever is the design requirement) for T < the time used in Step 2.

A5.  Power On Response

The purpose of this test is to verify that the UUT responds correctly to commands after power is applied to the UUT. The following test sequence shall be performed for the UUT using the normal power on sequence for the UUT.

  Step 1.  Power the UUT off.
  Step 2.  Send valid legal non-broadcast, non-mode commands to the UUT with a maximum intermessage gap of 1 ms.
  Step 3.  Power on the UUT and monitor all the UUT responses for 2 s starting from the first transmission of the UUT after power up.

The pass criteria shall be: 

  Step 3. NR until the first UUT transmission, and CS for the first transmission and all responses thereafter.

A6.  Data Wrap-Around

The purpose of this test is to verify that the UUT properly implements the data wrap-around capability. The following sequence shall be performed with random data patterns  for each data word. The messages used shall contain the maximum number of data words that the RT is capable of transmitting or receiving; that is, the maximum word count from the set of all messages defined for that RT.

  Step 1.  Send a receive command with the appropriate number of data words to the UUT at the design requirement receive wrap-around subaddress defined for the UUT.
  Step 2.  Send a transmit command to the UUT with the design requirement wrap-around subaddress and with the same word count as Step 1.

The pass criteria shall be:

  Step 1. CS
  Step 2. CS with each data word having the same bit pattern as the corresponding data word in Step 1.

A7.  RT to RT Validation

The following step and pass criteria shall be added to 5.2.2.5.3:

  Step 3.  Following the completion of Step 2, a Transmit Status mode command shall be issued to the UUT.

The pass criterion for Step 3 is "ME."

 A8.  Connector Polarity

Add the following as 4.2 to this document.

4.2  Connector Polarty: When performing tests for UUT's that use concentric connectors or inserts for each bus, observe polarity conventions ln connecting to the UUT's such that the center pin of the connector or insert shall be used for the high (positive) Manchester bi-phase signal. The inner ring shall be used for the low (negative) Manchester bi-phase signal.