21150
2.8
JTAG Signals
Table 11 describes the JTAG signals.
Table 11. JTAG Signals
Signal Name
Type
Description
JTAG serial data in. Signal tdi is the serial input through which
JTAG instructions and test data enter the JTAG interface. The
new data on tdi is sampled on the rising edge of tck. An
unterminated tdi produces the same result as if tdi were driven
high.
tdi
I
JTAG serial data out. Signal tdo is the serial output through
which test instructions and data from the test logic leave the
21150.
tdo
O
JTAG test mode select. Signal tms causes state transitions in
the test access port (TAP) controller. An undriven tms has the
same result as if it were driven high.
tms
tck
I
I
JTAG boundary-scan clock. Signal tck is the clock controlling
the JTAG logic.
JTAG TAP reset. When asserted low, the TAP controller is
asynchronously forced to enter a reset state, which in turn
asynchronously initializes other test logic. An unterminated
trst_l produces the same result as if it were driven high.
trst_l
I
Preliminary Datasheet
17
INTEL [ INTEL ]
