DS2196 datasheet(126/157 Pages) DALLAS

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DS2196

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Exit2-DR

While in this state, a rising edge on JTCLK with JTMS high will put the controller in the Update-DR

state and terminate the scanning process. A rising edge on JTCLK with JTMS low will enter the Shift-

DR state.

Update-DR

A falling edge on JTCLK while in the Update-DR state will latch the data from the shift register path of

the Test registers into the data output latches. This prevents changes at the parallel output due to changes

in the shift register. 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.

Select-IR-Scan

All test registers retain their previous state. The instruction register will remain unchanged during this

state. With JTMS low, a rising edge of JTCLK moves the controller into the Capture-IR state and will

initiate a scan sequence for the Instruction register. JTMS high during a rising edge on JTCLK puts the

controller back into the Test-Logic-Reset state.

Capture-IR

The Capture-IR state is used to load the shift register in the instruction register with a fixed value. This

value is loaded on the rising edge of JTCLK. If JTMS is high on the rising edge of JTCLK, the controller

will enter the Exit1-IR state. If JTMS is low on the rising edge of JTCLK, the controller will enter the

Shift-IR state.

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 registers, 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 thorough 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 shift register is halted 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 low will put the controller in the Update-IR state. The controller

will loop back to Shift-IR if JTMS is high during a rising edge of JTCLK in this state.

DS2196 Datasheet(PDF) 126 Page - Dallas Semiconductor