ht82a821r Holtek Semiconductor Inc., ht82a821r Datasheet - Page 16

• Manufacturer Part Number: ht82a821r
• Description: Ht82a821r -- Usb Audio Mcu
• Manufacturer: Holtek Semiconductor Inc.

USB Interface
The HT82A821R have 3 Endpoints (EP0 ~EP2). EP0 supports Control transfer. EP1 supports Interrupt transfer. EP2
supports Isochronous transfer.
These registers, including USC (20H), USR (21H), UCC (22H), AWR (23H), STALL (24H ), SIES (25H), MISC (26H),
SETIO (27H), FIFO0 (28H), FIFO1 (29H), FIFO2 (2AH) used for the USB function.
The FIFO size of each FIFO is 8 byte (FIFO0), 8 byte (FIFO1), 384 byte (FIFO2), and total are 400 bytes.
URD (bit7 of USC) is USB reset signal control function definition bit.
The USR (USB endpoint interrupt status register) register is used to indicate which endpoint is accessed and to select
serial bus (USB). The endpoint request flags (EP0F, EP1F, EP2F) are used to indicate which endpoints are accessed. If
an endpoint is accessed, the related endpoint request flag will be set to 1 and the USB interrupt will occur (if USB in-
terrupt is enabled and the stack is not full). When the active endpoint request flag is served, the endpoint request flag
has to be cleared to 0 by software.
Rev. 1.10
Bit No.
Bit No.
5~6
3~7
0
1
2
3
4
7
0
1
2
RESUME
RMWK
SUSP
URST
Label
V33O
Label
EP0F
EP1F
EP2F
URD
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R
Reset
Reset
0
0
0
0
0
1
0
0
0
USC (20H) Register
USR (21H) Register
Read only, USB suspend indication. When this bit is set to 1 (set
by SIE), it indicates the USB bus enters suspend mode. The USB in-
terrupt is also triggered on changing from low to high of this bit.
USB remote wake-up command. It is set by MCU to force the USB
host leaving the suspend mode.
USB reset indication. This bit is set/cleared by USB SIE. This bit is
used to detect USB reset event on USB bus. When this bit is set to
be initialized.
USB resume indication. When the USB leaves suspend mode, this
bit is set to 1 (set by SIE). When the RESUME is set by SIE, an in-
terrupt will be generated to wake-up the MCU. In order to detecting
the suspend state, MCU should set USBCKEN and clear SUSP2 (in
UCC register) to enable the SIE detecting function. The RESUME
will be cleared while the SUSP is going 0 . When MCU is detecting
the SUSP, the RESUME (causes MCU to wake-up) should be re-
membered and token into consideration.
0/1: Turn-off/on V33O output
Undefined bit, read as 0 .
USB reset signal control function definition
1: USB reset signal will reset MCU
0: USB reset signal cannot reset MCU
When this bit is set to 1 (set by SIE). It indicates the endpoint 0 is
accessed and an USB interrupt will occur. When the interrupt has
been served, this bit should be cleared by software.
When this bit is set to 1 (set by SIE). It indicates the endpoint 1 is
accessed and an USB interrupt will occur. When the interrupt has
been served, this bit should be cleared by software.
When this bit is set to 1 (set by SIE). It indicates the endpoint 2 is
accessed and an USB interrupt will occur. When the interrupt has
been served, this bit should be cleared by software.
Undefined bit, read as 0 .
1 , this indicates an USB reset is occurred and an USB interrupt will
16
Functions
Functions
HT82A821R
June 29, 2007