Datasheet

DS21352/DS21552
101 of 137
Figure 19-2 TAP CONTROLLER STATE DIAGRAM
19.3 INSTRUCTION REGISTER
The instruction register contains a shift register as well as a latched parallel output and is 3 bits in length.
When the TAP controller enters the Shift-IR state, the instruction shift register will be connected between
JTDI and JTDO. While in the Shift-IR state, a rising edge on JTCLK with JTMS LOW will shift the data
one stage towards the serial output at JTDO. A rising edge on JTCLK in the Exit1-IR state or the Exit2-
IR state with JTMS HIGH will move the controller to the Update-IR state. The falling edge of that same
JTCLK will latch the data in the instruction shift register to the instruction parallel output. Instructions
supported by the DS21352/552 with their respective operational binary codes are shown in Table 19-1.
1
0
0
1
11
1
1
1
11
11
11
00
0
0
0
1
0
0
00
1
1
00
0
0
Select
DR-Scan
Capture DR
Shift DR
Exit DR
Pause DR
Exit2 DR
Update DR
Select
IR-Scan
Capture IR
Shift IR
Exit IR
Pause IR
Exit2 IR
Update IR
Test Logic
Reset
Run Test/
Idle
0