SMJ320C6414 Datasheet, PDF (74/133 Pages) Texas Instruments – FIXED-POINT DIGITAL SIGNAL PROCESSORS

SMJ320C6414, SMJ320C6415, SMJ320C6416
FIXEDĆPOINT DIGITAL SIGNAL PROCESSORS
SGUS050A − JANUARY 2004 − REVISED MARCH 2004
IEEE 1149.1 JTAG compatibility statement
The SMJ320C6414/15/16 DSP requires that both TRST and RESET be asserted upon power up to be properly
initialized. While RESET initializes the DSP core, TRST initializes the DSP’s emulation logic. Both resets are
required for proper operation.
While both TRST and RESET need to be asserted upon power up, only RESET needs to be released for the
DSP to boot properly. TRST may be asserted indefinitely for normal operation, keeping the JTAG port interface
and DSP’s emulation logic in the reset state.
TRST only needs to be released when it is necessary to use a JTAG controller to debug the DSP or exercise
the DSP’s boundary scan functionality.
For maximum reliability, the SMJ320C6414/15/16 DSP includes an internal pulldown (IPD) on the TRST pin to
ensure that TRST will always be asserted upon power up and the DSP’s internal emulation logic will always be
properly initialized.
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 a pullup resistor on TRST.
When using this type of JTAG controller, assert TRST to initialize the DSP after power up and externally drive
TRST high before attempting any emulation or boundary scan operations. Following the release of RESET, the
low-to-high transition of TRST must be “seen” to latch the state of EMU1 and EMU0. The EMU[1:0] pins
configure the device for either Boundary Scan mode or Emulation mode. For more detailed information, see
the terminal functions section of this data sheet.
EMIF device speed
The rated EMIF speed, referring to both EMIFA and EMIFB, of these devices only applies to the SDRAM
interface when in a system that meets the following requirements:
− 1 chip-enable (CE) space (maximum of 2 chips) of SDRAM connected to EMIF
− up to 1 CE space of buffers connected to EMIF
− EMIF trace lengths between 1 and 3 inches
− 166-MHz SDRAM for 133-MHz operation (applies only to EMIFA)
− 143-MHz SDRAM for 100-MHz operation
Other configurations may be possible, but timing analysis must be done to verify all AC timings are met.
Verification of AC timings is mandatory when using configurations other than those specified above. TI
recommends utilizing I/O buffer information specification (IBIS) to analyze all AC timings.
To properly use IBIS models to attain accurate timing analysis for a given system, see the Using IBIS Models
for Timing Analysis application report (literature number SPRA839).
To maintain signal integrity, serial termination resistors should be inserted into all EMIF output signal lines (see
the Terminal Functions table for the EMIF output signals).
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