Datasheet

SCANSTA111
www.ti.com SNLS060K –AUGUST 2001–REVISED APRIL 2013
This signature compactor is used to compress serial data shifted in from the local scan chain, into a 16-bit
signature. This signature can then be shifted out for comparison with an expected value. This allows users to test
long scan chains in parallel, via Broadcast or Multi-Cast addressing modes, and check only the 16-bit signatures
from each module. The LFSR is initialized with a value of 0000 Hex upon reset.
32-BIT TCK COUNTER REGISTER
The 32-bit TCK counter register enables BIST testing that requires n TCK cycles, to be run on a parked LSP
while another 'STA111 port is being tested. The CNTRSEL instruction can be used to load a count-down value
into the counter register via the active scan chain. When the counter is enabled (via the CNTRON instruction),
and the LSP is parked, the local TCKs will stop and be held low when terminal count is reached.
The TCK counter is initialized with a value of 00000000 Hex upon reset.
Table 11. Dedicated GPIO Register
n
(HDL only)
BIT 7 6 5 4 3 2 1 0
Description Input Input Input Input Output Output Output Output
Table 12. Shared GPIO Register
n
BIT 7 6 5 4 3 2 1 0
Description Reserved Reserved Reserved Reserved Reserved Input (TDI) Output (TDO) Output (TMS)
Used in N N N N N Y Y Y
Silicon
Default Value 0 0 0 0 0 0 0 0
SPECIAL FEATURES
TRANSPARENT MODE
While this mode is activated, the selected LSP n ports will follow the backplane ports. TRST
n
is a buffered
version of TRST
B
, TCK
n
is a buffered version of TCK
B
, TMS
n
is a buffered version of TMS
B
, TDO
n
is a buffered
version of TDI
B
and TDO
B
is a buffered version of TDI
n
. TRIST
B
and TRIST
n
are asserted when the state
machine is in either the Shift-DR or Shift-IR states. The unselected LSPs are placed in the PARKTLR state, and
their clocks are gated after 512 TCK
B
clock cycles.
Transparent Mode is controlled by 8 new instructions, TRANSPARENT0 through TRANSPARENT7. Transparent
Mode overrides any other active mode. When one of the transparent mode instruction is shifted into the
instruction register and the tap controller goes through the UPDATE-IR state, TRST
n
will go high, and TMS
n
will
go low. This will force the targets connected to the LSP
n
ports to go into the RTI state. Then as the 'STA111
state machine goes into the RTI state, all of the LSP
n
signals will follow the back-plane signals. This is identical
to the method that is typically used to unpark an LSP. The 'STA111 will remain in this mode until a TRST
B
is
asserted or a power cycle forces a reset. Once in the Transparent Mode, the 'STA111 will not be able to be reset
by a 5 TMS high reset.
The sequence of operations to use Transparent Mode on an LSP are as follows (example uses LSP
0
):
1. IR-Scan the 'STA111 address into the instruction register (address a 'STA111).
2. IR-Scan the TRANSPARENT0 instruction to enable Transparent Mode on LSP
0
. Transparent Mode is
enabled when the TAP enters the RTI state at the end of this shift operation (TRST
0
, TDO
0
, TMS
0
and TCK
0
become buffered versions of TRST
B
, TDI
B
, TMS
B
and TCK
B
and TDO
B
becomes a buffered version of TDI
0
).
NOTE
Transparent Mode will persist until the 'STA111 is reset using TRST
B
. The GOTOWAIT
and SOFTRESET instructions will not work in this mode.
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