Texas Instruments TMS320C6454 - Manual (Page 97)

www.ti.com
PRODUCT PREVIEW
7.3.4 Preserving Boundary-Scan Functionality on RGMII and DDR2 Memory Pins
TMS320C6454
Fixed-Point Digital Signal Processor
SPRS311A – APRIL 2006 – REVISED DECEMBER 2006
Peripherals used for booting, like I2C and HPI, are automatically enabled after device reset. It is not
possible to disable these peripherals after the boot process is complete.
The C64x+ Megamodule also allows for software-driven power-down management for all of the C64x+
megamodule components through its Power-Down Controller (PDC). The CPU can power-down part or
the entire C64x+ megamodule through the power-down controller based on its own execution thread or in
response to an external stimulus from a host or global controller. More information on the power-down
features of the C64x+ Megamodule can be found in the TMS320C64x+ Megamodule Reference Guide
(literature number
SPRU871 ).
When the RGMII mode of the EMAC is not used, the DV
DD15
, DV
DD15MON
, V
REFHSTL
, RSV13, and RSV14
pins can be connected directly to ground (V
SS
) to save power. However, this will prevent boundary-scan
from functioning on the RGMII pins of the EMAC. To preserve boundary-scan functionality on the RGMII
pins, DV
DD15
, V
REFHSTL
, RSV14, and RSV13 should be connected as follows:
•
DV
DD15
and DV
DD15MON
- connect these pins to the 1.8-V I/O supply (DV
DD18
).
•
V
REFHSTL
- connect to a voltage of DV
DD18
/2. The DV
DD18
/2 voltage can be generated directly from the
DV
DD18
supply using two 1-k
Ω
resistors to form a resistor divider circuit.
•
RSV13 - connect this pin to ground (V
SS
) via a 200-
Ω
resistor.
•
RSV14 - connect this pin to the 1.8-V I/O supply (DV
DD18
) via a 200-
Ω
resistor.
Similarly, when the DDR2 Memory Controller is not used, the V
REFSSTL
, RSV11, and RSV12 pins can be
connected directly to ground (V
SS
) to save power. However, this will prevent boundary-scan from
functioning on the DDR2 Memory Controller pins. To preserve boundary-scan functionality on the DDR2
Memory Controller pins, V
REFSSTL
, RSV11, and RSV12 should be connected as follows:
•
V
REFSSTL
- connect to a voltage of DV
DD18
/2. The DV
DD18
/2 voltage can be generated directly from the
DV
DD18
supply using two 1-k
Ω
resistors to form a resistor divider circuit.
•
RSV11 - connect this pin to ground (V
SS
) via a 200-
Ω
resistor.
•
RSV12 - connect this pin to the 1.8-V I/O supply (DV
DD18
) via a 200-
Ω
resistor.
Submit Documentation Feedback C64x+ Peripheral Information and Electrical Specifications 97