Datasheet

SCANSTA111
www.ti.com SNLS060K –AUGUST 2001–REVISED APRIL 2013
Figure 11. Local Scan Port Synchronization on Second Pass
Figure 12. Synchronization of the Three Local Scan Ports
This moves the local chain TAP Controllers to the synchronization state (Run-Test/Idle), where they stay until
synchronization occurs. If the next state of the 'STA111 TAP Controller is Run-Test/Idle, TMS
n
is connected to
TMS
B
and the local TAP Controllers are synchronized to the 'STA111 TAP Controller as shown in Figure 12. If
the next state after Update-IR were Select-DR, TMS
n
would remain low and synchronization would not occur until
the 'STA111 TAP Controller entered the Run-Test/Idle state, as shown in Figure 11.
Each local port has its own Local Scan Port Controller. This is necessary because the LSPN can be configured
in any one of eight (8) possible combinations. Either one, some, or all of the local ports can be accessed
simultaneously. Configuring the LSPN is accomplished with Mode Register
0
, in conjunction with the UNPARK
instruction.
The LSPN can be unparked in one of seven different configurations (Si device), as specified by bits 0-2 of Mode
Register
0
. Using multiple ports presents not only the task of synchronizing the 'STA111 TAP Controller with the
TAP Controllers of an individual local port, but also of synchronizing the individual local ports to one another.
When multiple local ports are selected for access, it is possible that two ports are parked in different states. This
could occur when previous operations accessed the two ports separately and parked them in the two different
states. The LSP Controllers handle this situation gracefully. Figure 12 shows the UNPARK instruction being used
to access LSP
0
, LSP
1
, and LSP
2
in series (Mode Register
0
= XXX0X111 binary). LSP
0
and LSP
1
become active
as the 'STA111 controller is sequenced through the Run-Test/Idle state. LSP
2
remains parked in the Pause-DR
state until the 'STA111 TAP Controller is sequenced through the Pause-DR state. At that point, all three local
ports are synchronized for access via the active scan chain.
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