Texas Instruments TMS320C6454 - Manual (Page 67)

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PRODUCT PREVIEW
3.6 JTAG ID (JTAGID) Register Description
3.7 Pullup/Pulldown Resistors
TMS320C6454
Fixed-Point Digital Signal Processor
SPRS311A – APRIL 2006 – REVISED DECEMBER 2006
Table 3-13. Device Status Register (DEVSTAT) Field Descriptions (continued)
Bit Field Value Description
3:0 BOOTMODE[3:0] Boot mode configuration bits
Shows the status of what device boot mode configuration is operational.
BOOTMODE[3:0]
[Note: if selected for boot, the corresponding peripheral is automatically enabled after device reset.]
0000 No boot (default mode)
0001 Host boot (HPI)
0010 Reserved
0011 Reserved
0100 EMIFA 8-bit ROM boot
0101 Master I2C boot
0110 Slave I2C boot
0111 Host boot (PCI)
1000 Reserved
thru
1111
For more detailed information on the boot modes, see Section 2.4 , Boot Sequence.
The JTAG ID register is a read-only register that identifies to the customer the JTAG/Device ID. For the
C6454 device, the JTAG ID register resides at address location 0x02A8 0008. For the actual register bit
names and their associated bit field descriptions, see
Figure 3-11 and Table 3-14 .
31 28 27 12 11 1 0
VARIANT PART NUMBER MANUFACTURER
LSB
(4-bit) (16-bit) (11-bit)
R-n R-0000 0000 1000 1010b 0000 0010 111b R-1
LEGEND: R = Read only; -n = value after reset
Figure 3-11. JTAG ID (JTAGID) Register - 0x02A8 0008
Table 3-14. JTAG ID (JTAGID) Register Field Descriptions
Bit Field Value Description
31:28 VARIANT Variant (4-Bit) value. The value of this field depends on the silicon revision being
used. For more information, see the TMS320C6455/54 Digital Signal Processor
Silicon Errata (literature number
SPRZ234 ).
Note: the VARIANT field may be invalid if no CLKIN1 signal is applied.
27:12 PART NUMBER Part Number (16-Bit) value. C6454 value: 0000 0000 1000 1010b.
11:1 MANUFACTURER Manufacturer (11-Bit) value. C6454 value: 0000 0010 111b.
0 LSB LSB. This bit is read as a "1" for C6454.
Proper board design should ensure that input pins to the C6454 device always be at a valid logic level and
not floating. This may be achieved via pullup/pulldown resistors. The C6454 device features internal pullup
(IPU) and internal pulldown (IPD) resistors on most pins to eliminate the need, unless otherwise noted, for
external pullup/pulldown resistors.
An external pullup/pulldown resistor needs to be used in the following situations:
•
Device Configuration Pins: If the pin is both routed out and 3-stated (not driven), an external
pullup/pulldown resistor must be used, even if the IPU/IPD matches the desired value/state.
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