Maxim-integrated DS4830 Optical Microcontroller Instrukcja Użytkownika Pobierz pdf (Strona 150)

DS4830 User’s Guide

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20.1 – TAP Controller

The TAP controller is a synchronous state machine that responds to changes at the TMS and TCK signals. Based on its

state transition, the controller provides the clock and control sequence for TAP operation. The performance of the TAP is

dependent on the TCK clock frequency. The maximum TCK clock frequency should be limited to 1/8 the system clock

frequency. This section provides a brief description of the state machine and its state transitions. The state diagram in

Figure 20-1 summarizes the transitions caused by the TMS signal sampling on the rising edge at TCK. The TMS signal

value is presented adjacent to each state transition in the figure.

TEST-LOGIC-RESET

RUN-TEST

-IDLE

SELECT-DR-SCAN

EXIT2-DR

CAPTURE-DR

SHIFT-DR

EXIT1-DR

AUSE-DR

UPDATE-DR

SELECT

-IR-SCAN

EXIT2-IR

CAPTURE-IR

SHIFT

-IR

EXIT1-IR

PAUSE-IR

UPDATE-IR

Figure 20-2: TAP Controller State Diagram

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Maxim-integrated DS4830 Optical Microcontroller Instrukcja Użytkownika Strona 150