DS3112 Datasheet, PDF (106/135 Pages) Dallas Semiconductor – TEMPE T3/E3 Multiplexer 3.3V T3/E3 Framer and M13/E13/G.747 Mux

DS3112
Shift-IR
In this state, the shift register in the Instruction register is connected between JTDI and JTDO and shifts
data one stage for every rising edge of JTCLK towards the serial output. The parallel register, as well as
all Test registers remain at their previous states. A rising edge on JTCLK with JTMS high will move the
controller to the Exit1-IR state. A rising edge on JTCLK with JTMS low will keep the controller in the
Shift-IR state while moving data one stage through the Instruction shift register.
Exit1-IR
A rising edge on JTCLK with JTMS low will put the controller in the Pause-IR state. If JTMS is high on
the rising edge of JTCLK, the controller will enter the Update-IR state and terminate the scanning
process.
Pause-IR
Shifting of the Instruction register is ha lted temporarily. With JTMS high, a rising edge on JTCLK will
put the controller in the Exit2-IR state. The controller will remain in the Pause-IR state if JTMS is low
during a rising edge on JTCLK.
Exit2-IR
A rising edge on JTCLK with JTMS high will put the controller in the Update-IR state. The controller
will loop back to the Shift-IR state if JTMS is low during a rising edge of JTCLK in this state.
Update -IR
The instruction shifted into the Instruction shift register is latched into the parallel output on the falling
edge of JTCLK as the controller enters this state. Once latched, this instruction becomes the current
instruction. A rising edge on JTCLK with JTMS low will put the controller in the Run-Test-Idle state.
With JTMS high, the controller will enter the Select-DR-Scan state.
11.3 Instruction Register And Instructions
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 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 DS3112 and their respective operational binary codes are shown in Table 11.3A.
INSTRUCTION CODES Table 11.3A
INSTRUCTIONS
SAMPLE/PRELOAD
BYPASS
EXTEST
CLAMP
HIGH-Z
IDCODE
SELECTED REGISTER
Boundary Scan
Bypass
Boundary Scan
Bypass
Bypass
Device Identification
INSTRUCTION CODES
010
111
000
011
100
001
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