Maxim-integrated MAXQ622 Manual do Utilizador descarregar pdf (Página 190)

MAXQ612/MAXQ622 User’s Guide

Maxim Integrated 13-3

13.2.2 Run-Test-Idle

As illustrated in Figure 13-1, the run-test-idle state is simply an intermediate state for getting to one of the two state

sequences in which the controller performs meaningful operations:

• Controller state sequence (IR-scan) or

• Data register state sequence (DR-scan)

13.2.3 IR-Scan Sequence

The controller state sequence allows instructions (e.g., debug and system programming) to be shifted into the instruc-

tion register starting from the select-IR-scan state. In the TAP, the instruction register is connected between the TDI

input and the TDO output. Inside the IR-scan sequence, the capture-IR state loads a fixed binary pattern (001b) into the

3-bit shift register and the shift-IR state causes shifting of TDI data into the shift register and serial output to TDO, least

significant bit first. Once the desired instruction is in the shift register, the instruction can be latched into the parallel

instruction register (IR[2:0]) on the falling edge of TCK in the update-IR state. The contents of the 3-bit instruction shift

register and parallel instruction register (IR[2:0]) are summarized with respect to the TAP controller states in Table 13-2.

Figure 13-1. TAP Controller State Diagram

TEST-LOGIC-RESET

RUN-TEST-IDLE

SELECT-DR-SCAN

EXIT2-DR

CAPTURE-DR

SHIFT-DR

EXIT1-DR

PAUSE-DR

UPDATE-DR

SELECT-IR-SCAN

EXIT2-IR

CAPTURE-IR

SHIFT-IR

EXIT1-IR

PAUSE-IR

UPDATE-IR

1 2 ... 185 186 187 188 189 190 191 192 193 194 195 ... 254 255

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