AT43USB353M_04 Datasheet, PDF (64/95 Pages) ATMEL Corporation – Low Cost Full-speed USB Microcontroller with Embedded Hub, ADC and PWM

USB Registers
Hub Address Register
– HADDR
The following sections describe the registers of the AT43USB353M’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
6
5
$1FEF
SAEN
HADD6 HADD5
Read/Write
R/W
R/W
R/W
Initial Value
0
0
0
4
HADD4
R/W
0
3
HADD3
R/W
0
2
HADD2
R/W
0
1
HADD1
R/W
0
0
HADD0
R/W
0
HADDR
• Bit 7 – SAEN: Single Address Enable
The Single Address Enable bit allows the microcontroller to configure the AT43USB353M 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]
Function Address
Register – FADDR
The USB function contains an address register that contains the function address assigned by
the host. This Function Address Register must be programmed by the microcontroller once it
has received a SET_ADDRESS request from the host and completed the status phase of the
transaction. After power up or reset, this register will contain the value of 0x00.
Function Address Register – FADDR
Bit
7
6
5
4
$1FEE
FEN
FADD6
FADD5
FADD4
Read/Write
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
3
FADD3
R/W
0
2
FADD2
R/W
0
1
FADD1
R/W
0
0
FADD0
R/W
0
FADDR
• Bit 7 – FEN: Function Enable
The Function Enable bit (FEN) allows the firmware to enable or disable the function end-
points. The firmware will set this bit after receipt of a reset through the hub, SetPortFea-
ture[PORT_RESET]. Once this bit is set, the USB hardware passes to and from the host.
When the Single Address bit is set, the condition of FEN is ignored.
• Bit 6..0 – FADD6...0: Function Address[6:0]
64 AT43USB353M
3307B–USB–4/04