PRODUCT PREVIEW

TMS320C6454

Fixed-Point Digital Signal Processor

www.ti.com

SPRS311A –APRIL 2006 –REVISED DECEMBER 2006

7.18 IEEE 1149.1 JTAG

7.18.1 JTAG Device-Specific Information

7.18.1.1 IEEE 1149.1 JTAG Compatibility Statement

For maximum reliability, the C6454 DSP includes an internal pulldown (IPD) on the TRST pin to ensure that TRST will always be asserted upon power up and the DSP'sinternal emulation logic will always be properly initialized when this pin is not routed out. JTAG controllers from Texas Instruments actively drive TRST high. However, some third-party JTAG controllers may not drive TRST high but expect the use of an external pullup resistor on TRST. When using this type of JTAG controller, assert TRST to initialize the DSP after powerup and externally drive TRST high before attempting any emulation or boundary scan operations.

7.18.2JTAG Peripheral Register Description(s)

7.18.3JTAG Electrical Data/Timing

Table 7-105. Timing Requirements for JTAG Test Port (see Figure 7-75)

 

 

 

-720

 

NO.

 

 

-850

UNIT

 

 

-1000

 

 

 

 

 

 

 

MIN

MAX

1

tc(TCK)

Cycle time, TCK

35

ns

3

tsu(TDIV-TCKH)

Setup time, TDI/TMS/TRST valid before TCK high

10

ns

4

th(TCKH-TDIV)

Hold time, TDI/TMS/TRST valid after TCK high

9

ns

Table 7-106. Switching Characteristics Over Recommended Operating Conditions for JTAG Test Port

(see Figure 7-75)

 

 

 

-720

 

 

NO.

PARAMETER

-850

 

UNIT

-1000

 

 

 

 

 

 

 

MIN

 

MAX

2

td(TCKL-TDOV)

Delay time, TCK low to TDO valid

-3

 

18 ns

 

 

1

 

 

 

 

TCK

 

 

 

 

 

 

2

 

2

 

 

TDO

 

 

 

 

 

 

3

4

 

 

 

 

 

 

 

 

TDI/TMS/TRST

 

 

 

 

 

 

Figure 7-75. JTAG Test-Port Timing

 

 

 

216

C64x+ Peripheral Information and Electrical Specifications

Submit Documentation Feedback

Page 216
Image 216
Texas Instruments TMS320C6454 warranty Jtag Device-Specific Information, Ieee 1149.1 Jtag Compatibility Statement