Maxim Integrated MAXQ7667 - Manual (Page 194)

11-5 __________________________________________________________________________________________________________
MAXQ7667 User’s Guide
11.4 TAP Controller Operation
The MAXQ7667 TAP controller is formed by a finite state machine that provides 16 operational states for access control. The TAP state
control is achieved through host manipulation of the TMS and TCK signals. The TMS signal is sampled at the rising edge of TCK and
decoded by the TAP controller to control movement between the TAP states. The TDI input and TDO output are meaningful once the
TAP is in a serial shift state. This section provides a brief description of the TAP controller state machine and its state transitions.
The state diagram in Figure 11-2 summarizes the transitions caused by the TMS signal sampling on the rising edge at TCK. The TMS
signal value is shown 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
PAUSE-DR
UPDATE-DR
SELECT-IR-SCAN
EXIT2-IR
CAPTURE-IR
SHIFT-IR
EXIT1-IR
PAUSE-IR
UPDATE-IR
1
0
1 1 1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0 0
1 1
0 0
Figure 11-2. TAP Controller State Diagram