USB 2.0 test coverage done with one-button operation - Embedded.com

USB 2.0 test coverage done with one-button operation

Palo Alto, Calif.—Grappling with complex and tedious USB tests? Help's on the way. Test-and-measurement house Agilent Technologies Inc . is adding USB 2.0 (Universal Serial Bus) receiver test functions to its 81134A 3.35-GHz pulse pattern generator, essentially automating USB test with single-button operation. The package is priced at less than $10,000.

The test library package is called the N5990A Option 102 . A typical test setup uses Option 102 with the company's 2-channel 81134A pulse pattern generator and a wideband oscilloscope such as one of Agilent's Infiniium scopes.

Wither Interoperability?

Even though USB is so widely used, Agilent claims design test coverage isn't sufficient to ensure against all end-user interoperability problems. During my discussion with Agilent General Manager Gerd Koffmane (at the company's High-Speed Digital Test Segment, Digital Verification Solutions Division, Electronic Measurements Group ), he pointed out that an undetected design problem in an area such as receiver testing can have a tremendous impact on end-users.

“Intermittent system crashes can greatly increase support costs,” noted Koffmane. “A problem found after shipment can cost one thousand times more than if found during the design phase.”

“For designers,” Koffmane added, “the USB standard remains very complex. As such, it's tough to do compliance with short scripts and little C programs. The only way out is test automation.”

Receiver Tests

That's where Agilent's new receiver test functions come in. Complementing the firm's existing N5416A USB 2.0 compliance test suite, the additional receiver tests provide test coverage and the automation Koffmane says is so necessary. The receiver test functions complement the N5416A's USB transmitter test compliance suite.

The new functions provide Pass/Fail information as well as detailed test results—at a glance. “You essentially pick and choose which test you need,” says Koffmane. “At the beginning of a design you might only need a few of the many prescribed tests. That way a designer can focus on what's required initially, working up to a scenario where the design passes all of the spec's tests.”

Agilent's N5990A option 102 USB 2.0 receiver test library includes automated receiver intra-pair skew tests, and jitter tolerance tests. It also supports carrier skew, maximum sync filed, and squelch tests, and can measure common-mode voltage and make differential sensitivity tests.

That lets you debug and characterize stages to verify the sensitivity and tolerance of your device, under key parameters such as amplitude, jitter, and delay between differential signals.

In addition to requiring the 81134A pulse pattern generator and Infiniium scope, the package's jitter tolerance tests require an external signal generator for jitter generation via clock modulation.

For more information, contact Agilent Technologies Inc., 395 Page Mill Rd., Palo Alto, Calif. 94303. Phone: 800-829-4444. Fax: (650) 752-5300.

Agilent Technologies , 650-752-5000, www.agilent.com/find/81134A

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