Datasheet

SCANSTA111

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SNLS060K –AUGUST 2001–REVISED APRIL 2013

CNTRSEL: This instruction inserts the 32-bit TCK counter shift register into the active scan chain. This allows the

user to program the number of n TCK cycles to send to the parked local ports once the CNTRON instruction is

issued (e.g., for BIST operations). Note that to ensure completion of countdown, the 'STA111 should receive at

least n TCK

pulses.

CNTRON: This instruction enables the TCK counter. The counter begins counting down on the first rising edge of

TCK

following the Update-IR TAP controller state and is decremented on each rising edge of TCK

thereafter.

When the TCK counter reaches terminal count, 00000000 Hex, TCK

of all parked LSP's is held low. This

function overrides Mode Register

TCK control bit (bit-3).

If the CNTRON instruction is issued when the TCK counter is 00000000 (terminal count) the local TCKs of

parked LSPs will be gated. The counter will begin counting on the rising edge of TCK

when the TCK counter is

loaded with a non-zero value following a CNTRSEL instruction (see BIST Support in Special Features section for

an example).

CNTROFF: This instruction disables the TCK counter, and TCK

control is returned to Mode Register

(bit 3).

DEFAULT_BYPASS: This instruction selects the Bypass register to be the default for SCANSTA111 commands

that do not explicitly require a data register. The default after RESET is the Device ID register.

Figure 9. Local Scan Port Synchronization from Parked-TLR State

Figure 10. Local Scan Port Synchronization from Parked-RTI State

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