at43usb320a ATMEL Corporation, at43usb320a Datasheet - Page 77

• Manufacturer Part Number: at43usb320a
• Description: Full-speed Usb Microcontroller With An Embedded Hub
• Manufacturer: ATMEL Corporation

USB Registers
Hub Address Register
– HADDR
1443E–USB–4/04
The following sections describe the registers of the AT43USB320A’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.
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 AT43USB320A into
a single address or a composite device. Once this capability is enabled, the hub endpoint 0
(HEP0) is converted from a control endpoint to a programmable function endpoint FEP3; all
the endpoints would then operate on the single address.
• Bit 6..0 – HADD6...0: Hub Address[6:0]
Read/Write
Initial Value
$1FEF
Bit
SAEN
R/W
7
0
HADD6
R/W
6
0
HADD5
R/W
5
0
HADD4
R/W
4
0
HADD3
R/W
3
0
HADD2
R/W
2
0
AT43USB320A
HADD1
R/W
1
0
HADD0
R/W
0
0
HADDR
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