JP2022040950A - Error rate measuring device and parameter acquisition method - Google Patents

Abstract

To save time by reducing the number of operations for testing with Cursor.SOLUTION: An error rate measuring device 1 includes a data transmission unit 11 that measures a response time when a parameter value change instruction is given during link training to manage the link status, and sequentially transmits a change instructions to all presets to an object W to be measured as a parameter value in the state of recovery equalization phases 2 or 3 during at least one link training, and a data receiving unit 13 that sequentially receives and acquires each Cursor value corresponding to all the Presets according to the change instruction sequentially transmitted from the data transmitting unit 11 from the object W to be measured.SELECTED DRAWING: Figure 1

Description

The present invention relates to an error rate measuring device that measures a bit error rate (BER) of a device under test (DUT), and in particular, a parameter value during link training for managing the state of a link. The present invention relates to an error rate measuring device for measuring the response time when a change instruction is given and a parameter acquisition method.

As disclosed in, for example, Patent Document 1 below, the error rate measuring device uses a test signal of a known pattern including fixed data as a measured object in a state where the measured object (DUT) is transitioned to a signal pattern folding state. Conventionally known as a device for measuring the bit error rate by transmitting and comparing the measured signal received by returning from the measured object with the transmission of this test signal on a bit-by-bit basis. ..

By the way, in this kind of error rate measuring device, in addition to measuring the bit error rate of the object to be measured, the response time when a parameter value change instruction is given during link training for managing the link state is measured. May be done.

For example, in the case of PCI Express (hereinafter abbreviated as PCIe), one of the compliance test items is a response time test (Tx Link Equation Response Time test). This response time test is performed by the following procedures (1) to (5) based on the flowchart of FIG.

(1) Link training for setting the object to be measured in the loopback state (Loopback Active) is started (ST11).
(2) During the link training, the error rate measuring device sets the default as the parameter value of the object to be measured in the state of Recovery Evaluation Phase 2 or 3 of "Recovery" in the LTSSM (Link Training and Status State Machine) of FIG. 5 (for example, initial). Value: Presset0) is instructed to change (ST12).
(3) The response time until the object to be measured changes to the actually instructed Presset (for example, initial value: Presset0) is measured by an error rate measuring device (ST13). At this time, the object to be measured returns the Cursor value: cursor value corresponding to the instructed Default (for example, initial value: Default0) to the error rate measuring device (ST14). This Cursor value is a unique value of the object to be measured, and the error rate measuring device can know this value through this test.
(4) The processes of ST12 to ST14 are incremented in order from Presset0 (initial value) as parameter values and executed up to Presset9, and the processes are performed a total of 10 times (ST15).
(5) Of the Presss 0 to 9 obtained in ST15, the Cursor value corresponding to the desired Presset is set, and the response time is measured by setting the bit for performing the response time test with the set Cursor value. (ST16).

It should be noted that each Cursor value is possessed by the object to be measured and the error rate measuring device in advance, and can be arbitrarily set for each Presset 0 to 9. Therefore, it is not possible to know which value each Cursor value has between the object to be measured and the error rate measuring device.

Japanese Unexamined Patent Publication No. 2007-274474

However, in the conventional error rate measuring device, it is necessary to perform one Presset test for each link training, and the Cursor value is acquired each time the link training is performed. Therefore, in order to perform the test by Cursor, the test by Presset must be repeated 10 times in advance, which has a problem that not only the operation is complicated but also it takes time.

Therefore, the present invention has been made in view of the above problems, and provides an error rate measuring device and a parameter acquisition method capable of reducing the number of operations for performing a test by Cursor and shortening the time. The purpose is.

In order to achieve the above object, the error rate measuring device according to claim 1 of the present invention measures the response time when a parameter value change instruction is given during link training for managing the state of the link. The error rate measuring device 1
A data transmission unit 11 that sequentially transmits a change instruction to all Pressets as the parameter value in the state of Recovery Measurement Phases 2 or 3 during at least one link training, and
It is characterized by including a data receiving unit 13 for sequentially receiving and acquiring each Cursor value corresponding to all the Presses according to a change instruction sequentially transmitted from the data transmitting unit from the measured object.

The parameter acquisition method of the error rate measuring device according to claim 2 of the present invention measures the error rate measuring the response time when a parameter value change instruction is given during link training for managing the link state. It is a method of acquiring device parameters.
A step of sequentially transmitting a change instruction to all Pressets as the parameter value in the state of Recovery Measurement Phase 2 or 3 during at least one link training, and a step of sequentially transmitting the change instruction to the measured object W.
It is characterized by including a step of sequentially receiving and acquiring each Cursor value corresponding to all the Presses according to the change instruction transmitted sequentially from the measured object.

According to the present invention, in measuring the response time from the instruction to change the parameter value to the object to be measured during the link training until the parameter value is actually changed to the instructed parameter value, a test by Cursor is performed. It is possible to reduce the number of operations for this purpose and shorten the time. This is useful because the work can be streamlined, for example, when it is desired to continuously perform only the Cursor test of a plurality of objects to be measured. Furthermore, if it is performed during one link training, the work efficiency can be further improved.

It is a block diagram which shows the outline of the connection structure of the error rate measuring apparatus which concerns on this invention, and the object to be measured. It is a flowchart which shows the test procedure including the parameter acquisition method of the error rate measuring apparatus which concerns on this invention. It is a figure which shows an example of the Cursor value corresponding to the Presset which the error rate measuring apparatus which concerns on this invention acquires from a measured object. It is a block diagram which shows the outline of the other connection structure of the error rate measuring apparatus which concerns on this invention, and the object to be measured. It is an example of a link state management mechanism, and is a state transition diagram of LTSSM. It is a flowchart which shows the test procedure including the conventional parameter acquisition method.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the attached drawings.

[About the outline of the present invention]
In the error rate measuring device according to the present invention, for example, a device conforming to the PCIe standard, which is a connection standard for an expansion bus or an expansion slot, is set as a measured object (DUT), and the measured object is a signal pattern folding state (FIG. 5). A test signal of a known pattern including fixed data is transmitted to the measured object in a state of transitioning to the “Loopback” state of LTSSM), and the measured signal received by returning from the measured object along with the transmission of this test signal. The bit error rate is measured by comparing the reference signal with the reference signal in bit units.

In particular, in the present invention, the parameter value actually instructed after the instruction to change the parameter value (Preset: preset or Cursor: cursor) is given to the object to be measured during the link training for managing the state of the link. In measuring the response time until the change, the purpose is to reduce the number of operations for performing the test by Cursor to shorten the time.

The parameter value is a value previously possessed by the object to be measured and the error rate measuring device, and is used to determine the amount of Transmitter Equalization. Specifically, for example, as parameter values corresponding to the amplitude for each tap (enfasis amount of preshoot and de-emphasis), there are Press0 to 9 and a Cursor value corresponding to each Presset of Presset0 to 9. Each Cursor value can be arbitrarily set for each Presset of Press 0 to 9, and it is not known which value the measured object and the error rate measuring device have each other.

As shown in FIG. 1, the error measuring device 1 is roughly configured with a setting unit 2, a pattern generator 3, and an error detector 4 in order to achieve the above object, and once for managing the state of the link. It has a function of transmitting all the instruction for changing the parameter values (Preset 0 to 9) to the object W to be measured during the link training of the above and acquiring all the Cursor values corresponding to them at once. Note that this operation is not limited to one link training, but may be during a plurality of link trainings.

As shown in FIG. 1, the object to be measured W is equipped with a link state management unit W1 by the LTSSM (Link Training and Status State Machine) of FIG. 5 as a link state management mechanism for managing the link state, and is equipped with a data reception unit W2. , A data transmission unit W3 is provided and is roughly configured. Hereinafter, each configuration of the object to be measured W and the error rate measuring device 1 will be described.

[About the composition of the object to be measured]
The data receiving unit W2 receives a parameter value (a parameter value from the pattern generator 3 of the error rate measuring device 1 during link training for managing the state of the link when performing a response time test (Tx Link Equilation Response Time test). Receive the change instruction of Presset or Cursor).

Further, when measuring the bit error rate, the data receiving unit W2 transmits a test signal of a known pattern including fixed data in a state of transitioning to a signal pattern folding state (“Loopback” state of LTSSM in FIG. 5). Received from the pattern generator 3 of the error rate measuring device 1.

When the data transmission unit W3 tests the response time, the data reception unit W2 sequentially transmits all the Pressets (Presset0) as parameter values from the pattern generator 3 of the error rate measuring device 1 during one link training. When the change instruction of 9) is received, the data of each Curser value corresponding to all the received Pressets (Pressets 0 to 9) is sequentially transmitted to the error rate measuring device 1. That is, the procedure in which the error rate measuring device 1 sends a change instruction of Presset 0 to the measured object W and the measured object W returns the Cursor value corresponding to Presset 0 to the error rate measuring device 1 is 1 from Press 0 to 9. Repeat during link training. Note that this operation is not limited to one link training, but may be during a plurality of link trainings.

Further, when the data transmitting unit W3 measures the bit error rate, when the data receiving unit W2 receives a test signal of a known pattern from the pattern generator 3 of the error rate measuring device 1, it responds to the received test signal. The signal is returned to the error rate measuring device 1 as a signal to be measured and transmitted.

[About the configuration of the error rate measuring device]
The setting unit 2 makes various settings related to the measurement of the bit error rate. Specifically, the setting unit 2 sets the initial value of the Presset as the measurement condition and the number of times the Presset is measured in order to test the response time by the Presset as the parameter value. For example, when the initial value of Presset is set to "0" and the number of times of Presset measurement is set to "2", the response time test by Presset0,1 is performed during one link training. When the initial value of Presset is set to "3" and the number of times of Presset measurement is set to "5", the response time test by Presset 3, 4, 5, 6, 7 is performed during one link training. Note that this operation is not limited to one link training, but may be during a plurality of link trainings.

Further, the setting unit 2 sets the Cursor value corresponding to any of Press 0 to 9 as the parameter value acquired from the object W to be measured based on the test procedure including the parameter acquisition method described later, and the response time according to the set Cursor value. Set a bit to perform the test.

The pattern generator 3 generates data based on, for example, a training sequence based on the state of PCIe LTSSM or a known pattern, and includes a data transmission unit 11 and a trigger generation unit 12.

When the data transmission unit 11 tests the response time using the parameter value (Preset or Cursor), the data transmission unit 11 is required for the response time test using the parameter value according to an instruction from the link state management unit 13a described later of the error detector 4. Generates a training sequence (Training Sequence Ordered Sets: TS OS).

The training sequence is a data pattern sequence for the error rate measuring device 1 and the measured object W to exchange parameters, and is a data and setting unit for instructing the measured object W to change a parameter value (Preset or Cursor). Data of the initial value of Presset as the measurement condition set in 2, the data of the number of times of measurement of Presset, the data of the Cursor value corresponding to any of Press 0 to 9 set in the setting unit 2, and the response by the set Cursor value. Contains bit data and the like for time testing.

The data transmission unit 11 uses PRBS (pseudo-random bit. A pattern signal (test signal) is generated by a sequence) pattern or an arbitrary programmable pattern.

The trigger generation unit 12 generates a trigger as a timing signal. This trigger is generated when the data transmission unit 11 generates a training sequence including data of a parameter value (Preset or Cursor) change instruction, and is described later in the error detector 4 via an external cable or internal wiring. It is input to the receiving unit 13.

The error detector 4 receives data from the object W to be measured and detects an error, and includes a data receiving unit 13, a storage unit 14, and a display unit 15.

In the data receiving unit 13, a trigger is input from the trigger generating unit 12 of the pattern generator 3, and the data receiving unit W is actually instructed to change the parameter value (Preset or Cursor) to the measured object W during the link training. It has a function of measuring the response time until it is changed to the instructed parameter value, and includes a link state management unit 13a and an error detection unit 13b.

In the data receiving unit 13, the data transmitting unit 11 of the pattern generator 3 changes the parameter value (Preset or Cursor) with respect to the object W to be measured, starting from the trigger input from the trigger generating unit 12 of the pattern generator 3. The time when the instruction is transmitted (parameter value change instruction transmission time) is measured, and the measured time is stored in the storage unit 14 as log information.

The data receiving unit 13 measures the time (data receiving time) for receiving data from the object W whose parameter value is actually changed according to the instruction for changing the parameter value (Preset or Cursor) from the pattern generator 3. The data reception time and the response time measured by measuring the response time from the parameter value change instruction transmission time to the data reception time described above are stored in the storage unit 14 as log information.

The link state management unit 13a has an LTSSM as the same or equivalent mechanism as the link state management unit W1 mounted on the object W to be inspected, and operates according to a standard (for example, PCIe) to be used.

The link state management unit 13a recognizes the current link state of the link state management unit W1 of the measured object W by the training sequence communicated with the measured object W (data receiving unit W2, data transmitting unit W3). do. Specifically, the LTSSM value, the link speed, the presence / absence of loopback, the LTSSM transition pattern, the lane number for identifying the lane, the link number, the generation time and number of occurrences of the pattern signal, the amount of enhancement, and the equalizer on the receiving side. Obtain various information such as adjustment values.

In the communication between the error rate measuring device 1 and the measured object W, the link state management unit 13a is accompanied by transmission of a training sequence for grasping the current link state of the measured object W from the pattern generator 3. The current link state of the measured object W is managed by the training sequence received from the data transmission unit W3 of the measured object W, and the training sequence to be generated next is determined according to the current LTSSM state of the measured object W. Instruct the data transmission unit 11 of the pattern generator 3.

The error detection unit 13b includes a test signal of a known pattern generated by the data transmission unit 11 of the pattern generator 3 in a state where the object W to be measured is transitioning to loopback when measuring the bit error rate, and this test. The bit error rate is detected by comparing with the pattern signal that is folded back and input from the object W to be inspected as the signal is input.

The storage unit 14 has a parameter value (preset 0 to 9) corresponding to the parameter value (preset 0 to 9) acquired from the object W in accordance with a change instruction of the parameter value (Preset 0 to 9) in the state of Recovery Evaluation Phase 2 or 3 of LTSSM. Cursor: C-1, Main cursor: C0, Post cursor: C + 1)), Parameter value change instruction transmission time measured by data reception unit 13, data reception time, response time are stored as log information, and error detection unit. The bit error rate detected by 13b, various setting information related to bit error measurement, various information including the LTSSM value and the link speed managed by the link state management unit 13a are stored.

The display unit 15 is composed of a display such as a liquid crystal, and has a parameter value acquired from the object W to be measured (for example, each Cruiser value (C-1, C0, C + 1) corresponding to Presss 0 to 9 as shown in FIG. 3). ), Response time measured by the data receiving unit 13 (including the response time stored in the storage unit 14), measurement results including the bit error rate detected by the error detecting unit 13b, various settings related to bit error measurement. Display the screen etc.

[Response time measurement procedure]
Next, a procedure for measuring the response time including the parameter acquisition method by the error measuring device 1 configured as described above will be described with reference to FIG. Here, the response time from the instruction to change Presset 0 to 9 as the parameter value to the object W to be changed to the actually instructed Presset during the link training for managing the link state is shown. The case of measurement will be described as an example.

First, the initial value of Default as the measurement condition and the number of measurements of Default are set (ST1). Here, in order to test the response time by all Presses 0 to 9 as parameter values and acquire the cursor corresponding to all of Presses 0 to 9, the initial value of Presset is "0" and the number of times of measurement of Presset is "10". Are set respectively.

The data transmission unit 11 of the pattern generator 3 receives all the Pressets (Pressets 0 to 9) as parameter values for the object W to be measured based on the training sequence of PCIe according to the instruction from the link state management unit 13a of the error detector 4. A training sequence containing data instructing the change of is generated, and link training for setting the object W to the loopback state is started (ST2).

In addition, it is stipulated in the standard that the change instruction of each Presset (Presset 0 to 9) is given in the millisec order. Therefore, for example, when a training sequence including data instructing the change of Presset 0 is transmitted to the measured object W, the training sequence including the data instructing the next change of Presset 1 in the millisec order is sent to the measured object W. Will be sent.

When the link training is started, the data transmission unit 11 of the pattern generator 3 sets a change instruction of the Presset to the measured object W in the state of Recovery Measurement Phase 2 or 3 of the LTSSM during one link training in the setting unit 2. According to the measured measurement conditions (initial value of Presset and number of times of measurement of Presset), all Pressets (Presets 0 to 9) are sequentially instructed to be changed as parameter values of the object W to be measured (ST3). Note that this operation is not limited to one link training, but may be during a plurality of link trainings.

Then, when the object W to be measured sequentially receives instructions for changing all Pressets (Pressets 0 to 9) as parameter values from the data transmission unit 11 of the pattern generator 3, the Presset as the corresponding parameter values is received according to the received instructions. change. That is, when the object to be measured W receives a change instruction in the order of Press0 → Presset1 → Presset2 → ... → Presset8 → Presset9 as a parameter value from the data transmission unit 11 of the pattern generator 3, Presset0 → Presset1 → Presset2 → ... → The parameter values are sequentially changed in the order of Presset8 → Presset9.

At this time, in the data receiving unit 13 of the error detector 4, the data transmitting unit 11 of the pattern generator 3 starts from the trigger input from the trigger generating unit 12 of the pattern generator 3 as a parameter with respect to the object W to be measured. As a value, the time (parameter value change instruction transmission time) at which the change instructions of all Pressets (Pressets 0 to 9) are transmitted is measured, and the measured time is stored in the storage unit 14.

Then, the data receiving unit 13 of the error detector 4 measures the response time until the measured object W changes to each of Press 0 to 9 as the actually instructed parameter value (ST4), and each measured response time. Is stored in the storage unit 14.

At this time, the object W to be measured returns the respective Cursor values corresponding to Presss 0 to 9 as the parameter values instructed to be sequentially changed to the error rate measuring device 1, and the returned Cursor values are returned to the error rate measuring device. 1 (storage unit 14) holds (ST5).

Here, FIG. 3 shows an example of each Cursor value corresponding to the indicated parameter value: Presset 0-9. In FIG. 3, Presset 0 to 9 are represented as P0 to 9, and each Cursor value corresponding to Presset 0 to 9 is set in advance in the object W to be measured so that the total value of C-1, C, and C + 1 is 63. Has been done. In FIG. 3, for example, when the instructed parameter value is Presset5, C-1: 6, C: 57, and C + 1: 0 are returned from the measured object W as the Cursor values corresponding to Presset5. When the instructed parameter value is Presset7, C-1: 7, C: 45, and C + 1: 11 are returned from the measured object W as the Cursor values corresponding to Presset7.

Then, the error detector 4 sets the Cursor value corresponding to the desired Presset among the Presss 0 to 9 obtained in ST5 in the setting unit 2, and tests the response time with the set Cursor value. Bit is set by the setting unit 2 and the response time according to the Cursor value is measured (ST6).

[About other connection configurations]
By the way, instead of the connection configuration of FIG. 1, the response time can be tested by the parameter value (Preset or Cursor) in the connection configuration of FIG. 4 as well. In FIG. 4, the same or equivalent components as those in FIG. 1 are assigned the same number. Further, although not particularly shown, in the error rate measuring device 1 of FIG. 4, the pattern generator 3 has the functions of the data transmitting unit 11 and the trigger generating unit 12 of FIG. 1, and the error detector 4 is the data receiving unit 13. It has the functions of the storage unit 14 and the display unit 15. The data transmission unit 11 has a function of sequentially transmitting a change instruction to all the Pressets as a parameter value in the state of Recovery Equisition Phase 2 or 3 during one link training. Further, the data receiving unit 13 has a function of sequentially receiving and acquiring each Cursor value corresponding to all the Presses according to the change instruction sequentially transmitted from the data transmitting unit 11 from the measured object W. Note that this operation is not limited to one link training, but may be during a plurality of link trainings.

In the connection configuration of FIG. 4, the pattern generator 3 of the error rate measuring device 1 as a measuring instrument and the waveform measuring device (for example, an oscilloscope) 21 are connected by a cable, and the waveform is connected from the pattern generator 3 via the cable. A trigger is input to the measuring device 21. Further, the pattern generator 3 of the error rate measuring device 1 is connected to the object W to be measured and the waveform measuring device 21 with a cable via a divider 22. Further, the error detector 4 of the error rate measuring device 1 is connected to the object W to be measured and the waveform measuring device 21 via a divider 23, respectively, with a cable.

When the response time is tested by the parameter value (Preset or Cursor) in the connection configuration of FIG. 4, all the changes of the data (Presset 0 to 9 as the parameter value) transmitted by the pattern generator 3 of the error rate measuring device 1 are changed. The data to be instructed or the data to instruct to change the Cursor value corresponding to the Presset of any of Press 0 to 9 acquired from the object W to be measured) is branched into two by the divider 22. One of the data branched by the divider 22 is input to the waveform measuring device 21, and the other is input to the measured object W. Then, the data transmitted by the object W to be measured (including the data changed to all of Presset 0 to 9 as the parameter value and the respective Cursor values corresponding to Presset 0 to 9) is branched into two by the divider 23. The data branched by the divider 23 is input to the error detector 4 of the error rate measuring device 1 in order for one to perform link training with the object W to be measured, and the other is a waveform measuring device for observing changes in parameter values. It is input to 21. Then, by decoding the waveform of the data acquired by the waveform measuring device 21, the object W to be measured actually changes the parameter value (Presset or Cursor) after receiving the instruction to change the parameter value (Presset or Cursor). Measure the response time up to.

Further, in the above-described embodiment, PCIe has been described as an example as a standard, but the response time when the measurement object W is instructed to change the parameter value during the link training with the measurement object W. If it is a standard that requires the measurement of PCIe, it is not limited to PCIe alone.

As described above, according to the present embodiment, all the change instructions to Presset 0 to 9 are transmitted as parameter values in the state of Recovery Measurement Phase 2 or 3 during at least one link training, and the corresponding Cursor values are set. Since it is configured to acquire all at once, in the conventional method, 10 tests with Cursor were required before the test with Cursor, but with one test with Presset, the test with Cursor is possible and the number of operations is reduced. At the same time, the measurement time can be shortened. This is useful because the work can be streamlined, for example, when it is desired to continuously perform only the Cursor test of a plurality of objects to be measured. Furthermore, if all the parameter value (Preset 0 to 9) change instructions are sent to the object to be measured and the corresponding Cursor values are all acquired at once during one link training, the work can be further performed. Efficiency can be improved.

Although the best form of the error rate measuring device and the parameter acquisition method according to the present invention has been described above, the present invention is not limited by the description and drawings in this form. That is, it goes without saying that all other forms, examples, operational techniques, and the like made by those skilled in the art based on this form are included in the scope of the present invention.

1 Error rate measuring device 2 Setting unit 3 Pattern generator 4 Error detector 11 Data transmission unit 12 Trigger generation unit 13 Data reception unit 13a Link status management unit (LTSSM)
13b Error detection unit 14 Storage unit 15 Display unit 21 Waveform measuring device 22,23 Divider W Object to be measured (DUT)
W1 Link State Management Department (LTSSM)
W2 data receiver W3 data transmitter

Claims (2)

An error rate measuring device (1) that measures the response time when a parameter value change instruction is given during link training for managing the link status.
A data transmission unit (11) that sequentially transmits a change instruction to all the Pressets as the parameter value in the state of Recovery Measurement Phase 2 or 3 during at least one link training, and the object to be measured (W).
It is characterized by including a data receiving unit (13) for sequentially receiving and acquiring each Cursor value corresponding to all the Presses according to a change instruction sequentially transmitted from the data transmitting unit from the measured object. Error rate measuring device. It is a parameter acquisition method of an error rate measuring device that measures the response time when a parameter value change instruction is given during link training to manage the link status.
A step of sequentially transmitting a change instruction to all Pressets as the parameter value in the state of Recovery Measurement Phase 2 or 3 during at least one link training, and a step of sequentially transmitting a change instruction to the measured object (W).
A method for acquiring a parameter of an error rate measuring device, comprising:

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