SCANSTA111SM National Semiconductor, SCANSTA111SM Datasheet - Page 7

• Manufacturer Part Number: SCANSTA111SM
• Manufacturer: National Semiconductor

Specifications of SCANSTA111SM

• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Operating Temperature (max): 85C
• Package Type: FBGA
• Rad Hardened: No
• Lead Free Status / RoHS Status: Not Compliant

The 'STA111's scan port-configuration state-machine is used
to control the insertion of local scan ports into the overall scan
chain, or the isolation of local ports from the chain. From the
perspective of a system's (single) scan controller, each
'STA111 presents only one scan chain to the master. The
'STA111 architecture allows one or more of the 'STA111's lo-
cal ports to be included in the active scan chain.
Each local port can be parked in one of four stable states
(Parked-TLR, Parked-RTI, Parked-Pause-DR or Parked-
Pause-IR), either individually or simultaneously with other
local ports. Parking a chain removes that local chain from the
active scan chain. Conversely, a parked chain can be un-
parked, causing the corresponding local port to be inserted
into the active scan chain.
As shown in
uration state-machines allow each of the part's local ports to
occupy a different state at any given time. For example, some
ports may be parked, perhaps in different states, while other
ports participate in scan operations. The state-diagram shows
that some state transitions depend on the current state of the
TAP-control state-machine. As an example, a local port which
is presently in the Parked-RTI state does not become un-
parked (i.e., enter the Unparked 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-ma-
chine into specific states. For example, when a local port is in
the Unparked state, the 'STA111 receives the PARKRTI in-
struction and the TAP is transitioned through Run-Test/Idle
state, the Local Port controller enters the Parked-RTI state in
which TMS
n
Figure
will be held low until the port is later unparked.
4, the 'STA111's three scan port-config-
FIGURE 4. Local SCANSTA111 Port Configuration State Machine
7
Once the Park-RTI instruction has been updated into the in-
struction register the TAP MUST be transitioned through the
Run-Test/Idle state. While TMS
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 configuration. These instruc-
tions provide access to and control of various registers within
the 'STA111. This set of instructions includes:
Figure 5
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-ma-
chine, as shown in
BYPASS
EXTEST
SAMPLE/PRELOAD
IDCODE
MODESEL
MCGRSEL
LFSRSEL
illustrates how the 'STA111's state-machines inter-
Figure 4
or
Figure
n
is held low, all devices on
CNTRSEL
LFSRON
LFSROFF
CNTRON
CNTROFF
GOTOWAIT
5.
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