ht82a523r Holtek Semiconductor Inc., ht82a523r Datasheet - Page 23

• Manufacturer Part Number: ht82a523r
• Description: Ht82a523r -- Usb 2.0 Full Speed 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

There is a system clock control register implemented to select the clock used in the MCU. This register consists of USB
clock control bit (USBCKEN), second suspend mode control bit (SUSP2) and system clock selection (SYSCLK)
The following table defines which endpoint FIFO is selected, EPS2, EPS1 and EPS0.
The AWR register contains the current address and the remote wake-up function control bit. The initial value of the
AWR is 00H . The address value extracted from the USB command is not to be loaded into this register until the
SETUP stage is finished.
The STALL register shows whether the corresponding endpoint works properly or not. As soon as the endpoint works
improperly, the related bit in the STALL has to be set to 1 . The STALL will be cleared by the USB reset signal.
Rev. 1.30
Bit No.
Bit No.
Bit No.
1~7
0~3
4~7
0
1
2
3
4
5
6
7
0
USBCKEN
AD0~AD6
SYSCLK
SUSP2
WKEN
STL0~
STL3
Label
EPS0
EPS1
EPS2
Label
Label
RCtrl
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Accessing endpoint FIFO selection.
EPS2, EPS1, EPS0:
000: Select endpoint 0 FIFO
001: Select endpoint 1 FIFO
010: Select endpoint 2 FIFO
011: Select endpoint 3 FIFO
100: Reserved for future expansion, cannot be used
101: Reserved for future expansion, cannot be used
110: Reserved for future expansion, cannot be used
111: Reserved for future expansion, cannot be used
If the selected endpoints do not exist, the related functions are not available.
USB clock control bit. When this bit is set to 1 , it indicates that the USB clock is enabled.
Otherwise, the USB clock is turned-off.
This bit is used to reduce power consumption in suspend mode.
In normal mode, clear this bit to 0 (default)
In HALT mode, set this bit to 1 to reduce power consumption.
Must be set to 0
This bit is used to specify the system clock oscillator frequency used by the MCU. If a
6MHz crystal oscillator or resonator is used, this bit should be set to 1 . If a 12MHz
crystal oscillator or resonator is used. this bit should be cleared to 0 (default).
This bit is used to control whether there is 7.5K ohm resistor between D+ and Vbus
0: no 7.5k between D+ and Vbus (default)
1: has 7.5k between D+ and Vbus
Remote wake-up enable/disable (1/0)
USB device address
Set by users when the related USB endpoints are stalled. They are cleared by USB
reset and Setup Token event
Undefined bit, read as 0
STALL (24H) Definitions
AWR (23H) Definitions
UCC (22H) Definitions
23
Function
Function
Function
HT82A523R
May 13, 2008