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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
3:0
Field
BOOTMODE[3:0]
Value
Description
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.]
No boot (default mode)
Host boot (HPI)
Reserved
Reserved
EMIFA 8-bit ROM boot
Master I2C boot
Slave I2C boot
Host boot (PCI)
Reserved
0000
0001
0010
0011
0100
0101
0110
0111
1000
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
(4-bit)
PART NUMBER
(16-bit)
MANUFACTURER
(11-bit)
LSB
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
31:28
Field
VARIANT
Value
Description
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.
Part Number (16-Bit) value. C6454 value: 0000 0000 1000 1010b.
Manufacturer (11-Bit) value. C6454 value: 0000 0010 111b.
LSB. This bit is read as a "1" for C6454.
27:12
11:1
0
PART NUMBER
MANUFACTURER
LSB
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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