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E-25 – Texas Instruments TMS320C2XX User Manual

Page 537

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Emulation Design Considerations

E-25

Design Considerations for Using XDS510 Emulator

Figure E–15. TBC Emulation Connections for n JTAG Scan Paths

JTAG0

JTAGN

TDI

EMU1

TMS

TDO

EMU0

TRST

TCK

TDO

TCK

TRST

EMU1

EMU0

TMS

TDI

Clock

TDI1

TDI0

TCKO

TMS5/EVNT3

TMS4/EVNT2

TMS3/EVNT1

TMS2/EVNT0

TMS1

TMS0

TDO

TCKI

VCC

TBC

In the system design shown in Figure E–15, the TBC emulation signals TCKI,
TDO, TMS0, TMS2/EVNT0, TMS3/EVNT1, TMS5/EVNT3, TCKO, and TDI0
are used, and TMS1, TMS4/EVNT2, and TDI1 are not connected. The target
devices’ EMU0 and EMU1 signals are connected to V

CC

through pullup resis-

tors and tied to the TBC’s TMS2/EVNT0 and TMS3/EVNT1 pins, respectively.
The TBC’s TCKI pin is connected to a clock generator. The TCK signal for the
main JTAG scan path is driven by the TBC’s TCKO pin.

On the TBC, the TMS0 pin drives the TMS pins on each device on the main
JTAG scan path. TDO on the TBC connects to TDI on the first device on the
main JTAG scan path. TDI0 on the TBC is connected to the TDO signal of the
last device on the main JTAG scan path. Within the main JTAG scan path, the
TDI signal of a device is connected to the TDO signal of the device before it.
TRST for the devices can be generated either by inverting the TBC’s
TMS5/EVNT3 signal for software control or by logic on the board itself.