ht82a836r Holtek Semiconductor Inc., ht82a836r Datasheet - Page 36

• Manufacturer Part Number: ht82a836r
• Description: Usb Audio Mcu
• Manufacturer: Holtek Semiconductor Inc.

USB Function
The device includes a USB 1.1 interface which can be
used for data application data transfer. Five endpoints
are included in the USB function of this device.
USB Interface
The Interface in the HT82A836R device has 5 End-
points, known as EP0~EP4. Endpoint 0, EP0, is used for
Control transfer. Endpoints EP1 and EP4 are for Inter-
rupt transfer, while EP2 supports the Isochronous out
transfer. EP3 supports Isochronous in transfer. A set of
registers stored in the Data Memory is used for overall
control of the USB function. These control registers in-
clude, USC, USR, UCC, AWR, STALL, SIES and MISC.
There are also five FIFO registers with the names
FIFO0~FIFO4. The size of each FIFO is as follows:,
FIFO0-8 bytes, FIFO1-8 bytes, FIFO2-384 bytes,
FIFO3-32 bytes and FIFO4-64 bytes, giving a total of
496 bytes. The URD bit, which is bit7 of the USC register
is the USB reset signal control function definition bit.
USB Interface Registers
The USB setup, data management and endpoint control
in the device is controlled via a series of registers in the
Data Memory.
USC Register
The USC register is the register for the overall control of
the USB function. The initial status of this register is
80H.
Further explanation of each of the bits is given below:
Rev. 1.00
SUSP
The SUSP bit is the USB Suspend Indicator bit. When
this read-only bit is set to 1 by the SIE, it indicates
that the USB bus has entered the suspend mode. The
USB interrupt is also triggered when this bit changes
from low to high.
Watchdog Timer
36
RMWK
The RMWK read/write bit is the USB remote wake-up
command. It is set by the MCU to allow the USB host
to leave the suspend mode after an external wake-up.
URST
The URST read/write bit is the USB reset indication
bit. This bit is set and cleared by the USB SIE and indi-
cates a USB reset event on the USB bus. When this
bit is set to 1 , this indicates that a USB reset has oc-
curred and that a USB interrupt will be generated.
RESUME
The RESUME read only bit is used to indicate that the
USB has left the Suspend Mode. When the USB has
left the Suspend Mode, this read-only bit is set to 1
by the SIE. When the RESUME bit is set by SIE, an in-
terrupt will be generated to wake-up the MCU. In order
to detect the suspend state, the MCU should set the
USBCKEN bit and clear SUSP2 in the UCC register,
to enable the SIE detect function. The RESUME bit
will be cleared when SUSP goes to 0 . When the
MCU is detecting the SUSP, the condition of the RE-
SUME bit, which will wake-up the MCU, should be
noted and taken into consideration.
V33C
The V33C read/write bit is the control bit for the inter-
nally generated 3.3V supply for the USB interface.
PLLEN
The PLLEN read/write bit is the control bit for the inter-
nal Phase Locked Loop function.
CRCFG
The CRCFG read/write bit is the CRC error condition
failure flag. The CRCFG bit will be set by the hardware
however the CRCFG bit needs to be cleared using
firmware.
URD
The URD read/write bit is the USB reset signal control
function definition bit.
HT82A836R
March 20, 2008