ADSP-21061/ADSP-21061L
Connecting CLKIN to Pin 4 of the EZ-ICEheader is optional.
The emulator only uses CLKIN when directed to perform op-
erations such as starting, stopping and single-stepping multiple
ADSP-2106x in a synchronous manner. If you do not need these
operations to occur synchronously on the multiple processors,
simply tie Pin 4 of the EZ-ICE header to ground.
should be laid out as short as possible on your board. If TCK,
TMS and CLKIN are driving a large number of ADSP-2106x
(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.)
If synchronous multiprocessor operations are needed and
CLKIN is connected, clock skew between the multiple ADSP-
21061x processors and the CLKIN pin on the EZ-ICEheader
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
EMU should be treated as critical signals in terms of skew, and
If synchronous multiprocessor operations are not needed (i.e.,
CLKIN is not connected), just use appropriate parallel termina-
tion on TCK and TMS. TDI, TDO, EMU and TRST are not
critical signals in terms of skew.
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
EMU
5k⍀
*
TCK
TMS
TRST
TDO
SYSTEM
CLKIN
CLKIN
EMU
*
OPEN DRAIN DRIVER OR EQUIVALENT, i.e.,
Figure 7. JTAG Clocktree for Multiple ADSP-21061/ADSP-21061L Systems
REV. B
–13–
ADI [ ADI ]
