Waveform output method for RFID chip function test

Abstract

The invention relates to the technical field of radio frequency chip testing, and discloses a waveform output method for an RFID chip function test, which comprises the following steps of: analyzing an RFID instruction through an ATE machine and generating Pattern data; the Pattern data are sent to an AMO module to be subjected to waveform modulation; carrying out function test on the RFID chip by adopting a multi-station completely parallel test scheme; and a signal returned by the RFID chip is collected and demodulated, and demodulated data is displayed on a test interface of the ATE machine. According to the invention, a test scheme design that multiple stations are completely parallel is adopted, and the test stations are mutually independent, so that the test rate can be greatly improved, the mass production multi-station test requirements are met, and the advantages are obvious in a mass production environment; an external instrument or a special testing machine is not needed, testing is achieved through cooperation of the ATE machine and the AMO module, extra equipment investment is avoided, and cost is effectively saved.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency chip testing, and in particular to a waveform output method for functional testing of an RFID chip. Background Art

[0002] In conventional functional testing of RFID chips, the test process requires completing two core steps: waveform modulation and demodulation. Currently, most automatic test equipment (ATE) on the market only supports basic electrical signal output and cannot directly generate modulation waveforms that comply with RFID protocols (such as ASK and FSK modulation signals). Furthermore, they lack standardized waveform demodulation processing modules. The solutions commonly used in the industry suffer from three technical bottlenecks: The external instrument test mode uses external spectrum analyzers, signal generators and other dedicated instruments to achieve waveform modulation. The cost of a single instrument is usually between 100,000 and 300,000 yuan, resulting in a surge in production line testing costs. Due to limitations on dedicated test machines, some manufacturers have developed customized test equipment that is only compatible with specific chip models. When the test requirement switches from a 13.56MHz high-frequency chip to a 915MHz ultra-high-frequency chip, the entire hardware platform needs to be replaced, and the equipment reuse rate is less than 30%. Test efficiency is low. In the traditional single-station serial test mode, the test cycle for each chip is about 500ms. For a production line with an annual output of 10 million pieces, more than 20 test equipment must be configured, resulting in a double waste of site and labor costs. Summary of the Invention

[0003] The object of the present invention is to provide a waveform output method for RFID chip function testing to solve the above technical problems.

[0004] The purpose of the present invention can be achieved through the following technical solutions: The waveform output method for RFID chip functional testing uses three core modules to build a test system: ATE machine main control unit: Integrated 16-bit high-precision DAC (digital-to-analog converter), sampling rate up to 100MSPS, supports 0-5V peak-to-peak signal output; Built-in Pattern script engine, which can parse RFID instruction set and generate corresponding timing control signals; Equipped with an 8-channel parallel data acquisition card with 12-bit sampling accuracy, it supports real-time acquisition of signals below 1MHz.

[0005] AMO (Analog Modulation Output) module: It adopts a two-stage signal processing architecture: the front end is a 4th-order Butterworth low-pass filter (mainly passing 13.56Mhz), and the back end is a power amplifier circuit (with adjustable gain range of 0-20dB); Integrated automatic gain control (AGC) circuit, which can automatically adjust the amplification factor according to the input signal amplitude to ensure that the output waveform distortion is less than 1.5%; It supports ASK modulation depth continuously adjustable from 10% to 90%, and receives control commands from ATE machines through the SPI interface.

[0006] Multi-station parallel test interface unit: Adopting a hybrid architecture of time division multiplexing (TDM) and frequency division multiplexing (FDM), a single module supports eight test stations working independently; Each test station is equipped with an independent waveform conditioning circuit and isolation transformer to avoid signal crosstalk between stations (isolation > 40dB); Supports hot-swap function, which allows replacement of faulty test stations without interrupting testing.

[0007] Waveform output method flow: Protocol instruction parsing stage: The ATE machine receives the RFID test command (such as PCD_TO_PICC_CMD) input by the user and parses it into the underlying signal timing requirements through the built-in protocol stack; The script engine generates a corresponding pattern file based on the instruction type (such as anti-collision instruction, data read and write instruction), which contains parameters such as carrier start time, modulation mode, and data transmission rate.

[0008] Waveform modulation generation stage: The ATE machine sends the pattern data to the AMO module and outputs the modulation depth control signal (single-ended output can be 12vpp, differential output 24vpp); The AMO module first performs digital filtering on the pattern data, and then generates an ASK / FSK modulation waveform through an analog modulation circuit. The typical rise time is less than 50ns. In multi-station mode, each station AMO module receives an independent Pattern data stream and implements parallel modulation output.

[0009] Signal acquisition and demodulation stage: The ATE machine collects the reflected signal returned by the RFID chip through a sample-and-hold circuit, and the sampling frequency is 10 times the carrier frequency; The collected signal is processed using a coherent demodulation algorithm, and the original data is restored by mixing with a local reference carrier and low-pass filtering; The demodulated data is displayed in frame format on the test interface, including key parameters such as RSSI signal strength and bit error rate.

[0010] Multi-station collaborative control stage: The system's main control software uses a state machine model to manage each test station and supports the concept of "station group" (for example, 8 stations can be divided into 2 groups, each group independently executes different test items); Monitor the test progress of each station in real time. When the test of a station is completed, it will automatically trigger the loading of the next station to achieve seamless connection of the test process. It has the function of automatic isolation of faulty stations. When a station is detected to have failed three consecutive tests, it will be automatically marked as "maintenance status".

[0011] The beneficial effects of the present invention are as follows: a multi-station fully parallel test scheme design is adopted, and each test station is independent of each other, which can greatly improve the test rate and meet the multi-station testing needs of mass production, with significant advantages in a mass production environment; no external instrument or dedicated test machine is required, and testing is achieved through the cooperation of the ATE machine and the AMO module, avoiding additional equipment investment and effectively saving costs; the RFID operation instruction is embedded in the test module to convert to a pattern script, so that users can easily operate the RFID chip through instructions without in-depth understanding of the RFID communication mechanism, reducing the difficulty of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described below with reference to the accompanying drawings.

[0013] Figure 1 The present invention is a flow chart of a waveform output method for RFID chip function testing. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0015] See also Figure 1 As shown, the present invention is a waveform output method for RFID chip function testing, which will be explained from the perspectives of a single-station test scenario and a multi-station parallel test scenario.

[0016] Single-station test example Take the ISO 14443 Type A chip anti-collision test as an example: Instruction input stage: The test engineer inputs the anti-collision command "ANTICOLLISION" through the ATE machine operation interface, and the system automatically loads the corresponding protocol parameters (carrier frequency 13.56MHz, modulation mode 100% ASK, bit rate 106kbps).

[0017] Pattern generation phase: The ATE machine script engine generates a pattern file containing the following elements: Carrier on time: 500μs; Modulation start bit: Manchester code 0x00; Anti-collision command word: 0x93; Check code generation method: CRC-16; Waveform modulation stage: The ATE machine sends the pattern data to the AMO module and outputs a 2.5V modulation depth control signal (corresponding to 50% ASK modulation). The AMO module filters the pattern data (cutoff frequency 20MHz) and outputs a modulated waveform with a peak-to-peak value of 3V after power amplification. The rise time is approximately 40ns, and the output amplitude can be 12Vpp for single-ended output and 24Vpp for differential output.

[0018] Signal acquisition and demodulation: The ATE machine collects the reflected signal returned by the RFID chip at a sampling rate of at least 13.56 MHz, with a duration of 1 ms; The signal is demodulated using synchronous detection, and the Manchester coded data is converted into NRZ format and displayed in the "Anti-Collision Response" window of the test interface.

[0019] Result analysis: The system automatically parses the UID (unique identifier) information in the demodulated data, compares it with the standard database, and determines whether the chip's anti-collision function is normal. The entire test cycle is about 80ms, which is 6 times more efficient than traditional solutions.

[0020] Multi-station parallel testing example: In the 8-station mass production test scenario: Station group configuration: The 8 test stations are divided into two groups (stations 1-4 are group A, and stations 5-8 are group B). Group A performs high-frequency chip testing, and group B performs ultra-high-frequency chip testing. The two groups operate independently.

[0021] Parallel control flow: 0ms: Group A sends a high-frequency carrier (13.56MHz), and group B sends an ultra-high-frequency carrier (915MHz); 100ms: Group A completes the initialization test of the first chip, and Group B completes the power calibration of the first chip. 200ms: Group A starts testing the second chip, and group B simultaneously performs read and write tests on the second chip. 800ms: All eight test stations complete a round of testing, with a total testing efficiency of 10 wafers per second.

[0022] Inter-station isolation implementation: Each test station is equipped with an independent AMO sub-module and bandpass filter. The high-frequency station uses a 13.56MHz±100kHz filter, and the ultra-high-frequency station uses a 915MHz±5MHz filter. The measured crosstalk signal amplitude between stations is less than -40dBm, which does not affect normal testing.

[0023] Modulation depth control experiment: By changing the modulation depth control voltage output by the ATE machine, the modulation linearity of the AMO module is tested:

[0024] Experimental data shows that the linearity error of the AMO module is less than 3.5% within the modulation depth range of 10%-66%, meeting the RFID chip testing standard requirements.

[0025] The above is a detailed description of an embodiment of the present invention. However, the content is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A waveform output method for RFID chip function testing, characterized in that: The following steps are involved: Parse RFID instructions through ATE machine and generate pattern data; Send the Pattern data to the AMO module for waveform modulation to generate a modulation waveform that meets the requirements of the RFID chip; A multi-station fully parallel test solution is used to perform functional tests on RFID chips, with each test station being independent of each other; The signal returned by the RFID chip is collected and demodulated, and the demodulated data is displayed on the test interface of the ATE machine.

2. The waveform output method for RFID chip function test according to claim 1, characterized in that: The steps of parsing the RFID instruction and generating pattern data by the ATE machine include: The ATE machine receives the RFID test instructions input by the user and parses them into the underlying signal timing requirements through the built-in protocol stack; A corresponding Pattern file is generated according to the instruction type, and the Pattern file includes carrier on time, modulation mode and data transmission rate parameters.

3. The waveform output method for RFID chip function test according to claim 1, characterized in that: The step of sending the Pattern data to the AMO module for waveform modulation includes: The ATE machine sends pattern data to the AMO module and outputs a modulation depth control signal at the same time; The AMO module filters and amplifies the Pattern data to generate a modulated waveform, where the distortion of the modulated waveform is less than 1.5%.

4. The waveform output method for RFID chip function test according to claim 1, characterized in that: The steps of performing functional testing on the RFID chip using a multi-station fully parallel testing solution include: Each test station independently receives the pattern data stream sent by the ATE machine and realizes parallel modulation output; Each test station is managed in groups, and each group independently performs different test items; Monitor the test progress of each test station in real time to achieve seamless connection of the test process.

5. The waveform output method for RFID chip function test according to claim 1, characterized in that: The step of collecting and demodulating the signal returned by the RFID chip includes: The ATE machine collects the reflected signal returned by the RFID chip at a sampling frequency 10 times the carrier frequency; The collected signals are processed using a coherent demodulation algorithm to restore the original data and display it in a frame format. The frame format includes RSSI signal strength and bit error rate parameters.

6. The waveform output method for RFID chip function test according to claim 1, characterized in that: The ATE machine is further configured to display the demodulated data on a test interface in an intuitive manner. The test interface includes test data in a graphical or numerical form.

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