ADSP-21062/ADSP-21062L
Figure 6 shows JTAG scan path connections for systems that
contain multiple ADSP-2106x processors.
EMU should be treated as critical signals in terms of skew,
and should be laid out as short as possible on your board. If
TCK, TMS, and CLKIN are driving a large number of ADSP-
21062s (more than eight) in your system, then treat them as a
“clock tree” using multiple drivers to minimize skew. (See
Figure 7 “JTAG Clock Tree” and “Clock Distribution” in the
“High Frequency Design Considerations” section of the ADSP-
2106x User’s Manual, Second Edition.)
Connecting CLKIN to Pin 4 of the EZ-ICE header is optional.
The emulator only uses CLKIN when directed to perform
operations such as starting, stopping, and single-stepping mul-
tiple ADSP-2106xs in a synchronous manner. If you do not need
these operations to occur synchronously on the multiple proces-
sors, simply tie Pin 4 of the EZ-ICE header to ground.
If synchronous multiprocessor operations are not needed (i.e.,
CLKIN is not connected), just use appropriate parallel termi-
nation on TCK and TMS. TDI, TDO, EMU and TRST are
not critical signals in terms of skew.
If synchronous multiprocessor operations are needed and
CLKIN is connected, clock skew between the multiple ADSP-
21062 processors and the CLKIN pin on the EZ-ICE header
must be minimal. If the skew is too large, synchronous operations
may be off by one or more cycles between processors. For syn-
chronous multiprocessor operation TCK, TMS, CLKIN and
For complete information on the SHARC EZ-ICE, see the
ADSP-21000 Family JTAG EZ-ICE User's Guide and Reference.
TDI
TDO
TDI
TDO
TDI
TDO
5k⍀
*
TDI
TDO
TDI
TDO
TDI
TDO
TDI
5k⍀
*
EMU
TCK
TMS
TRST
TDO
SYSTEM
CLKIN
CLKIN
EMU
*OPEN DRAIN DRIVER OR EQUIVALENT, i.e.,
Figure 7. JTAG Clocktree for Multiple ADSP-2106x Systems
REV. C
–12–
ADI [ ADI ]
