Address Register

Address Register

The Address register contains the unique USB address that the USB decodes in peripheral mode (HOST_MODE_EN=0). In host mode (HOST_MODE_EN=1), the USB transmits this address with a TOKEN packet. This enables the USB to uniquely address any USB peripheral. In either mode the USB_EN bit in the Control register must be set. The register resets to 00h after the reset input activates or the USB decodes a USB reset signal. This action initializes the address register to decode address 00h, in keeping with the USB specification.

Note: The Buffer Descriptor Table Page register contains part of the 24 bit address used to compute the address where the current Buffer Descriptor Table (BDT) resides in system memory.

Table 4-14. Address Register

 

BIT

 

15

14

13

12

11

10

9

8

 

7

 

6

 

5

 

4

 

 

3

 

2

 

 

1

 

0

 

OFFSET

 

 

 

 

 

 

 

 

 

06h

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FIELD

 

 

 

BDT Page Register

 

 

 

 

 

 

 

 

Address Register

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BDT_BA[15:8]

 

 

 

_LSEN

 

 

 

 

 

 

 

ADDR[6:0]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESET

 

0

0

0

0

0

0

0

0

 

0

 

0

 

0

 

0

 

 

0

 

0

 

0

 

0

 

RW

 

R

R

R

R

R

R

R

R

 

R

 

R

 

R

 

R

 

R

R

R

R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 4-15. 16- Address Register Definitions

 

 

 

 

Bits

Field Name

 

Description

15:8

BDT_BA

 

BDT Base Address

 

 

 

This 8-bit value is the most-significant bits of the BDT base address, which

 

 

 

defines where the Buffer Descriptor Table resides at in system memory. The 16-

 

 

 

bit BDT base address is always aligned on 256-byte boundaries in memory.

7

LSEN

 

Low Speed Enable (valid for host mode only)

 

 

 

Tell the USB that the next token command written to the token register must be

 

 

 

performed at low speed. This lets the USB perform the necessary preamble

 

 

 

required for low-speed data transmissions.

6:0

ADDR[6:0]

 

USB Address

 

 

 

Defines the USB address that the USB decodes in peripheral mode or transmits

 

 

 

in host mode.

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Lantronix DSTni-EX manual 14. Address Register, 15. 16- Address Register Definitions