Corelis Boundary-Scan Blog Boundary-Scan Blog
Introduction
The QuadTAP/CFM and QuadTAP/CFM Expander cards were introduced last month as a convenient method to integrate Corelis JTAG hardware in Teradyne ICTs. We’ll go over the basics of using the main card and expanders for some common scenarios. For more detailed information about how to set up the QuadTAP/CFM and control the unit using Teradyne’s software, see Application Note #12-0312: Using Corelis Custom Function Modules with Teradyne ICTs.
Figure 1: QuadTAP & QuadTAP Expander Cards
The table below provides a summary of the equipment needed for different target requirements. Note that the hardware is capable of supporting either 4 or 5 signals on each TAP. A “4 signal” TAP means TRST is either unused or constrained by other means, usually fixed high through an ICT channel.
Table 1: Corelis CFM Configurations
Note: The Teradyne Custom Function Board is now called the Multi-Function Application Board. The function of the boards are the same and we will, for the purposes of this discussion, use the name Multi-Function Application Board.
Application Example 1: Four 4-Signal TAPs
In this scenario, we have four TAPs on the UUT and do not require control of the TRST signal. We can get by with just the QuadTAP/CFM and a single Expander card as shown in the diagram below.
Figure 2: QuadTAP/CFM Configuration for Four 4-Signal TAPs
The QuadTAP/CFM provides connections to TAP1 and TAP2 ports while the QuadTAP/CFM Expander module provides connections to TAP3 and TAP4 ports. The two CFMs are interconnected; the headers labeled TAP3 and TAP4 from the QuadTAP/CFM main card connect to the headers labeled TAP1 and TAP2 on the expander module.
Note: In order to utilize all eight MUX lines the first card should be installed in CFM slot 1 or 2 and the second should be installed in slot 3 or 4.
The TAP signals are routed to the tester interface through the Multi-Function Application Board top board. Each CFM is provided with 4 direct and 4 multiplexed connections to the tester interface. The four signals of TAP1 and TAP3 (TCK, TMS, TDI, TDO) use the direct path through the top board and their disconnect relays are mounted on the CFM while the four signals of TAP2 and TAP4 (TCK, TMS, TDI, TDO) use the multiplexed path and Multi-Function Application Board top board relays connect these signals to the interface.
Application Example 2: Four 5-Signal TAPs
In this scenario, we want to use four TAPs on the UUT and include the TRST signals. For this case we will need to populate all CFM slots to make use of all direct and muxed channels, as shown in the figure below.
Figure 3: QuadTAP/CFM Configuration for Four 5-Signal TAPs
The QuadTAP/CFM provides connections to TAP1 port while the QuadTAP/CFM Expander modules provide connections to TAP2, TAP3 and TAP4 ports. All four CFMs are interconnected; the headers labeled TAP2 on the QuadTAP CFM connect to the header labeled TAP1 on the expander module in position CFM-2. TAP3 from the QuadTAP module connects to TAP1 of the Expander module in position CFM-3. Finally, TAP4 from the QuadTAP/CFM main card connects to the header labeled TAP1 on the expander module in position CFM-4.
The TAP signals are routed to the tester interface through the Multi-Function Application Board top board. The four main JTAG signals (TCK, TMS, TDI, TDO) of TAP1, TAP2, TAP3 and TAP4 use the direct path through the top board and their disconnect relays are mounted on the CFM. The respective TRST# signals use the multiplexed path and Multi-Function Application Board top board relays connect these signals to the UUT interface.
Conclusion
The QuadTAP/CFM solution was designed to be configurable for all Teradyne ICT multiTAP requirements and, when used with ScanExpress software, offers advanced features such as IEEE-1149.6 support and direct I2C/SPI programming. Integrating a full-featured boundary-scan system such as Corelis ScanExpress directly with the ICT opens the door to greater test coverage and reduced expense.
