Case Studies
Digital I/O ASIC Testing
A customer needs to generate stimulus to test his Application Specific Integrated Circuits and to capture response from that ASIC.
The stimulus definition exists as an ASCII file with rows and columns of 1s and 0s. Each column corresponds to a different input pin of the ASIC and each rows corresponds to a different time tic (every 50 nanoseconds). The controlling baud clock runs at 10 MHz. The requirement is to record the digital response from the separate output pins of the ASIC as another ASCII file of 1s and 0s. Again, every clock tic generates another row, and each output pin has an associated column. The stimulus is independent of the response and there is no feedback from the response to alter the stimulus.
GAGE'S SOLUTION
The CompuGen 3250 is a 32 bit, 50 MS/s digital pattern generator card, which can be used to generate the stimulus. The CompuScope 3200 is a 32 bit, 100 MS/s digital input card that can be used to capture the response. These two cards provide the ideal digital stimulus-response instruments required for the application. The CS3200 and the CG3250 will both be externally clocked with the customer's 10 MHz baud clock.
The ASIC will be mounted on a test board equipped with two 3M mating connectors (input and output) for interfacing two CS3200 and CG3250 flat pleated foil cables. The cables guarantee 50 W impedance for each of the data lines using a Teflon based di-electric and a pleated copper foil, which also eliminates EMI radiation from the cable.
Gage recommended that the customer integrate a Gage CMOS Buffer Board directly onto the test board. The CMOS Buffer Board ensures that TTL signals provide the required current to drive the 50 W loads presented by every input of the CS3200.
Two software conversion utilities can be used to change the users ASCII pattern into a Gage readable .SIG file. This pattern will be output by CG3250 to the ASIC. Coming out of the ASIC the data will captured by CS3200 and converted back from .SIG file to ASCII data.
Because the customer did not require tight program control and had to get running quickly, Gage recommended operation under GageBit - Gage's free Windows-based high-speed digital input/output software. GageBit reads and stores data files in Gage's compact binary .SIG format. Software utilities that allow easy conversion back and forth from the customer's ASCII data file format are provided.
PRODUCT RECOMMENDED
CompuScope 3200 Digital Input Board
CMOS Buffer Board
CompuGen 3250 Digital Output Board
CG3250 Cable
GageBit Digital Input/Output Software (included with the purchase of CS3200 or CG3250)
GageScope to ASCII Signal File Conversion Utility ( free download from Gage Website )
ASCII to GageScope Signal File Conversion Utility ( free download from Gage Website )
This application note is provided "as is" without any warranties of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability or fitness for a particular purpose. Gage Applied Technologies further does not warrant the accuracy and completeness of the material contained herein. Gage Applied Technologies may make changes to this material, or to the products described in it, at any time without notice.
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