AT43USB355 datasheet(81/115 Pages) ATMEL

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AT43USB355

2603G–USB–04/06

USB Registers

The following sections describe the registers of the AT43USB355’s USB hub and function

units.

Reading a bit for which the microcontroller does not have read access will yield a zero value

result. Writing to a bit for which the microcontroller does not have write access has no effect.

Hub Address Register

– HADDR

The USB hub contains an address register that contains the hub address assigned by the

host. This Hub Address Register must be programmed by the microcontroller once it has

received a SET_ADDRESS request from the host. The USB hardware uses the new address

only after the status phase of the transaction is completed when the microcontroller has

enabled the new address by setting bit 0 of the Global State Register. After power-up or reset,

this register will contain the value of 0x00.

Hub Address Register – HADDR

• Bit 7 – SAEN: Single Address Enable

The Single Address Enable bit allows the microcontroller to configure the AT43USB355 into a

single address or a composite device. Once this capability is enabled, the hub end-point 0

(HEP0) is converted from a control end-point to a programmable function end-point FEP3; all

the end-points would then operate on the single address.

• Bit 6..0 – HADD6...0: Hub Address[6:0]

Bit

$1FEF

SAEN

HADD6

HADD5

HADD4

HADD3

HADD2

HADD1

HADD0

HADDR

Read/Write

R/W

Initial Value

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