Register

Common section for discussion of glossary terms. Please create a new topic for each term.
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Bradford Van Treuren
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Register

Post by Bradford Van Treuren »

This post is about the term "Register" and how that relates to P2654, P1687.1, 1687, and 1149.1-2013. Qualifying adjectives are also discussed.

From IEEE 1149.1-2013:
Register: Most often a Test Data Register, which is accessed by one or more specific instructions. (See Clause 9.)

selected test data register: A test data register is selected when it is required to operate by an instruction supplied to the test logic.

From IEEE 1687-2014:
Register: One or more storage elements that share a name and whose bits are arranged as a vector range (e.g., MyReg[31:0]).

data register: A set of one or more storage cells with a parallel input and a parallel output.

From IEEE 1149.10-2017:
instruction register: Refers to the IEEE 1149.1 instruction register. Bit “I” of the ICSU defined section in the scan packet indicates if there is an operation from a HSTAP and PEDDA to an IEEE 1149.1 instruction register. All other “instruction” registers, such as the IEEE 1500 wrapper instruction register, are treated as IEEE 1149.1 test data registers.
Bradford Van Treuren
Distinguished Member of Technical Staff
VT Enterprises Consulting Services
User avatar
Bradford Van Treuren
SJTAG Chair Emeritus
Posts: 152
Joined: Fri Nov 16, 2007 2:06 pm
Location: VT Enterprises Consulting Services, USA

Re: Register

Post by Bradford Van Treuren »

Jeff Rearick proposed this definition in an email.
Portal Register: an addressable register accessible through a functional interface to which writes and reads interact with a 1687 serial access network
Michele commented: Do we really need it in the definitions? It is not just part of the informative part of the standard, as a possible composition of the base elements (like the SIB)?
Bradford Van Treuren
Distinguished Member of Technical Staff
VT Enterprises Consulting Services