Texas Instruments TMS320C6454 Jtag ID Jtagid Register Description, Pullup/Pulldown Resistors

TMS320C6454

Fixed-Point Digital Signal Processor

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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.

3.6 JTAG ID (JTAGID) Register Description

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 3-11and 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.

3.7 Pullup/Pulldown Resistors

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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