TMS320F datasheet(348/389 Pages) TI

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Connections Between the Emulator and the Target System

C-13

Design Considerations for Using the XDS510 Emulator

C.6.3 Configuring Multiple Processors

Figure C–7 shows a typical daisy-chained multiprocessor configuration that

meets the minimum requirements of the IEEE 1149.1 specification. The

emulation signals are buffered to isolate the processors from the emulator and

provide adequate signal drive for the target system. One of the benefits of this

interface is that you can slow down the test clock to eliminate timing problems.

Follow these guidelines for multiprocessor support:

- The processor TMS, TDI, TDO, and TCK signals must be buffered through

the same physical device package for better control of timing skew.

- The input buffers for TMS, TDI, and TCK must have pullup resistors con-

nected to VCC to hold these signals at a known value when the emulator

is not connected. A resistor value of 4.7 k

Ω or greater is suggested.

- Buffering EMU0 and EMU1 is optional but highly recommended to provide

isolation. These are not critical signals and do not have to be buffered

through the same physical package as TMS, TCK, TDI, and TDO.

Figure C–7. Multiprocessor Connections

TDI

TDO

JTAG device

VCC

Emulator header

GND

TCK_RET

TCK

TDO

TDI

TMS

TRST

EMU1

EMU0

VCC

TMS320F Datasheet(PDF) 348 Page - Texas Instruments