PICMG considers boundary scan
Two working groups of the PCI Industrial Computer Manufacturers Group (PICMG) have taken the somewhat novel approach of making test techniques an integral part of board- and system-level standards. Mike Westermeier, a senior application engineer with ASSET, recently became a member of the subcommittee that is defining the MicroTCA standard. The groups defining this standard as well as the AdvancedTCA standard are considering the inclusion of boundary scan into both specifications. Mike’s extensive experience in boundary scan and system-level test at ASSET and several large system manufacturers will be very valuable to the working groups.
MicroTCA, or the Micro Telecommunications Computing Architecture, is a draft system architecture specification of a PICMG subcommittee. The MicroTCA draft standard allows Advanced Mezzanine Card (AdvancedMC or PICMG AMC .x) modules to be plugged into a system backplane. It is expected that the MicroTCA draft will become an official standard early next year.
Already a part of the MicroTCA draft standard is a requirement that each MicroTCA module support a boundary scan-compliant (IEEE 1149.1) interface. The working group has discussed the best way to implement a backplane connection to the 1149.1 interface. Under consideration are several architectural approaches, including star, ring and multi-drop configurations. Another alternative proposed to the subcommittee would route the JTAG channel over MicroTCA’s Intelligent Platform Management Bus (IPMB).
The AdvancedTCA ® (Advanced Telecommunications Computing Architecture) standard is being implemented in next-generation carrier-grade communications equipment. AdvancedTCA is actually a series of specifications that incorporates the latest advancements in high-speed interconnect technologies, next-generation processors and “improved reliability, manageability and serviceability.”
Including JTAG in the AdvancedTCA is currently being discussed by this committee. The AdvancedTCA specification defines a platform management system that includes an Intelligent Platform Management Interface (IPMI) and an Intelligent Platform Management Bus (IPMB). The IPMB provides out-of-band communications in the event the system and its bus fail. If the system were to fail, the IPMB could connect externally via AdvancedTCA’s Intelligent Chassis Management Bus (ICMB). The AdvancedTCA committee recently entertained a proposal that called for the IPMB to carry JTAG test commands and data between the Shelf Management Controller (ShMC) and the Baseboard Management Controller. A paper describing this proposal and written by G. Carlsson and others at Ericsson will be presented at the upcoming International Test Conference next month in Austin, Texas. For more information on ITC, click here.
Both the MicroTCA and the AdvancedTCA standards bodies have much to consider with regards to integrating JTAG into these standards. Comments and input from interested parties is encouraged. For more information about PICMG and its work click here. click here.
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