Maxim-integrated DS4830A Optical Microcontroller Instrukcja Użytkownika Pobierz pdf (Strona 160)

DS4830A User’s Guide

160

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

1 2 ... 155 156 157 158 159 160 161 162 163 164 165 ... 239 240

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Maxim-integrated DS4830A Optical Microcontroller Instrukcja Użytkownika Strona 160