Digital I/O scan modules are available in standard DIMM and SODIMM form factors to facilitate the enhanced testing of complex printed circuit boards.

JTAG Technologies, a leading world-wide provider of IEEE1149-compliant boundary-scan products, has introduced the JT 2127 series of digital I/O scan (DIOS) modules. The modules are available in standard dual inline memory module (DIMM) and small outline DIMM (SODIMM) form factors and facilitate the enhanced testing of complex printed circuit boards. When connected to a circuit board, a JT 2127 DIOS test module enhances regular device interconnect tests by exercising the board's connections and/or test-points in sync with native boundary-scan components.

Moreover, the modules feature carefully selected complex programmable logic devices (CPLDs) and an oscillator that can be programmed to perform more custom functional and pattern tests.

James Stanbridge, JTAG Technologies' Sales Manager UK, comments: 'The JT 2127 DIOS DIMM test modules provide a 'best-of-both-worlds' solution when it comes to implementing boundary-scan and functional tests'.

'For example, a target circuit board may contain elements - such as board-edge connectors, DIMM connectors and non-boundary-scan logic clusters - which may only be partially accessible by boundary-scan'.

'In such cases, the overall testability of the board is compromised, allowing some manufacturing faults to go undetected'.

'The DIOS modules overcome this problem by extending the reach of boundary-scan to include the testing of circuit board edge connectors and by providing extra I/O test points internal to the PCB to improve fault coverage'.

In addition, the module's hot-swap feature offers improved test throughput by allowing test targets to be connected/disconnected from the fixture without cycling power.

To facilitate the testing of boards not fitted with DIMM sockets, a DIOS module carrier (available separately) can be used to break-out the module's I/O into blocks of 32 channels.

These I/O channels can be further subgrouped into blocks of 16 channels.

To reduce scan chain length and improve test efficiency any number of 16-channel groups can be bypassed.

Selected channels can be interfaced with custom cabling to the board under test for low volume applications or interfaced with bed-of-nails fixtures for higher volume production.

The I/O channels are individually programmable as input, output, bi-directional or tri-state signals.

The DIMM DIOS modules feature intelligent sensing of voltage rails for power supply checking.

The mechanical form and pin arrangement of the DIMM DIOS modules follow the JEDEC Standard 21C allowing easy integration within a production test fixture using standard connectors or directly on a target PCB and providing access in close proximity to the test points.

Standard DIMM sockets pinouts include 100, 168, 184, 200, 240, 278 and 300 and small outline DIMM socket pinouts include 144, 200 and 214.

Up to 10 DIOS DIMM modules can be daisychained together in a mix of module types.

The modules are available immediately, priced GBP 795 (VAT may apply).

The DIOS DIMM carrier, also available immediately, is priced GBP 500 (VAT may apply).

Stanbridge concludes: 'The JT 2127 DIOS DIMM modules are truly multifunctional - and therefore lend themselves well to playing crucial roles in any test strategy'.

'Moreover, they're manufactured and supported by the market-leading and longest-established boundary-scan company in the business'.