SCANSTA111 National Semiconductor Corporation, SCANSTA111 Datasheet - Page 8

• Manufacturer Part Number: SCANSTA111
• Description: Enhanced Scan Bridge Multidrop Addressable Ieee 1149.1 Jtag Port
• Manufacturer: National Semiconductor Corporation

www.national.com
State Machines
state) until the ’STA111 receives an UNPARK instruction and
the ’STA111’s TAP state-machine enters the Run-Test/Idle
state.
Similarly, certain transitions of the scan port-configuration
state-machine can force the ’STA111’s LSP-control state-
machine into specific states. For example, when a local port
is in the Unparked state, the ’STA111 receives the PARKRTI
instruction and the TAP is transitioned through Run-Test/Idle
state, the Local Port controller enters the Parked-RTI state in
which TMS
Once the Park-RTI instruction has been updated into the
instruction register the TAP MUST be transitioned through
the Run-Test/Idle state. While TMS
on that local scan chain remain in their current TAP State
(the RTI TAP controller state in this example).
The ’STA111’s scan port-configuration state-machine imple-
ments part of the ’STA111’s Level-2 protocol. In addition, the
’STA111 provides a number of Level-2 instructions for func-
tions other than local scan port confguration. These instruc-
tions provide access to and control of various registers within
the ’STA111. This set of instructions includes:
n
will be held low until the port is later unparked.
(Continued)
FIGURE 5. Relationship Between SCANSTA111 State Machines
n
is held low, all devices
8
Figure 5 illustrates how the ’STA111’s state-machines inter-
act. The ’STA111-selection state-machine enables or dis-
ables operation of the chip’s three port-selection state-
machines. In ’STA111s which are selected via Level-1
protocol (either as individual ’STA111s or as members of
broadcast or multi-cast groups), Level-2 protocol commands
can be used to park or unpark local scan ports. Note that
most transitions of the port-configuration state-machines are
gated by particular states of the ’STA111’s TAP-control state-
machine, as shown in Figure 4 or Figure 5.
BYPASS
EXTEST
SAMPLE/PRELOAD
IDCODE
MODESEL
MCGRSEL
LFSRSEL
CNTRSEL
LFSRON
LFSROFF
CNTRON
CNTROFF
GOTOWAIT
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