Figure 11.4 Jtag Scan Path Connections For Multiprocessor Adsp-2106X Systems - Analog Devices ADSP-2106x SHARC User Manual

11 System Design
Figure 11.4 shows JTAG scan path connections for systems that contain
multiple ADSP-2106x processors.
Connecting CLKIN to pin 4 of the EZ-ICE header is optional. The emulator
only uses CLKIN when performing synchronous multiprocessor operations
such as starting, stopping, and single-stepping multiple ADSP-2106xs. 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.
If synchronous multiprocessor operations are needed and CLKIN is
connected, however, clock skew between the multiple ADSP-2106x 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 cycle between processors.
TCK, TMS, CLKIN (optional), and
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-2106xs (more
than eight) in your system, then treat them as a "clock tree" using multiple
drivers. (See "Clock Distribution" in the "High Frequency Design
Considerations" section of this chapter.) If synchronous multiprocessor
operations are not needed and CLKIN is not connected, just use appropriate
parallel termination on TCK and TMS. TDI, TDO, and
signals in terms of skew.
EZ-ICE
JTAG
Connector
TDI
TCK
TMS
Other
JTAG
EMU
Controller
TRST
TDO
CLKIN
optional

Figure 11.4 JTAG Scan Path Connections For Multiprocessor ADSP-2106x Systems

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EMU
should be treated as critical signals
ADSP-2106x
#1 JTAG
Device
(optional)
TDI TDO TDI
TRST
are not critical
ADSP-2106x
#n
TDO TDI TDO