Texas Instruments TMS320C6201 Reference Manual page 448

Emulation Design Considerations
15.9 Emulation Design Considerations
15.9.1 Using Scan Path Linkers
15-14
This section describes the use and application of the scan path linker (SPL),
which can simultaneously add all four secondary JTAG scan paths to the main
scan path. It also describes the use of the emulation pins and the configuration
of multiple processors.
You can use the TI ACT8997 scan path linker (SPL) to divide the JTAG
emulation scan path into smaller, logically connected groups of 4 to 16
devices. As described in the Advanced Logic and Bus Interface Logic Data
Book (literature number SCYD001), the SPL is compatible with the JTAG
emulation scanning. The SPL is capable of adding any combination of its four
secondary scan paths into the main scan path.
A system of multiple, secondary JTAG scan paths has better fault tolerance
and isolation than a single scan path. Since an SPL has the capability of adding
all secondary scan paths to the main scan path simultaneously, it can support
global emulation operations, such as starting or stopping a selected group of
processors.
TI emulators do not support the nesting of SPLs (for example, an SPL
connected to the secondary scan path of another SPL). However, you can
have multiple SPLs on the main scan path.
Although the ACT8999 scan path selector is similar to the SPL, it can add only
one of its secondary scan paths at a time to the main JTAG scan path. Thus,
global emulation operations are not assured with the scan path selector. For
this reason, scan path selectors are not supported.
You can insert an SPL on a backplane so that you can add up to four device
boards to the system without the jumper wiring required with nonbackplane
devices. You connect an SPL to the main JTAG scan path in the same way you
connect any other device. Figure 15–8 shows you how to connect a secondary
scan path to an SPL.