AMD AMD-K6-2/400 User Guide - Page 275
BoundaryScan Test Access Port (TAP), Test Access Port TAP Controller, Instruction Register IR
![]() |
View all AMD AMD-K6-2/400 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 275 highlights
23542A/0-September 2000 Preliminary Information AMD-K6™-2E+ Embedded Processor Data Sheet s TDO is never floated because the Boundary-Scan Test Access Port must remain enabled at all times, including during the Three-State Test mode. The Three-State Test mode is exited when the processor samples RESET asserted. 13.3 Boundary-Scan Test Access Port (TAP) The boundary-scan Test Access Port (TAP) is an IEEE standard that defines synchronous scanning test methods for complex logic circuits, such as boards containing a processor. The AMD-K6-2E+ processor supports the TAP standard defined in the IEEE Standard Test Access Port and Boundary-Scan Architecture (IEEE 1149.1-1990) specification. Test Access Port Boundary scan testing uses a shift register consisting of the serial interconnection of boundary-scan cells that correspond to each I/O buffer of the processor. This non-inverting register chain, called a Boundary Scan Register (BSR), can be used to capture the state of every processor pin and to drive every processor output and bidirectional pin to a known state. Each BSR of every component on a board that implements the boundary-scan architecture can be serially interconnected to enable component interconnect testing. The TAP consists of the following: s Test Access Port (TAP) Controller-The TAP controller is a synchronous, finite state machine that uses the TMS and TDI input signals to control a sequence of test operations. See "TAP Controller State Machine" on page 260 for a list of TAP states and their definition. s Instruction Register (IR)-The IR contains the instructions that select the test operation to be performed and the Test Data Register (TDR) to be selected. See "TAP Registers" on page 255 for more details on the IR. s Test Data Registers (TDR)-The three TDRs are used to process the test data. Each TDR is selected by an instruction in the Instruction Register (IR). See "TAP Registers" on page 255 for a list of these registers and their functions. Chapter 13 Test and Debug 253
![](/manual_guide/products/amd-amdk62400-user-guide-2771ebc/275.png)