HT45B0K Holtek Semiconductor, HT45B0K Datasheet - Page 10

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HT45B0K

Manufacturer Part Number
HT45B0K
Description
SPI to USB Bridge
Manufacturer
Holtek Semiconductor
Datasheet
Rev 1.00
UCC Register
Name
POR
R/W
Bit
The UCC register is the system clock control register implemented to select the clock used by the
MCU. This register consists of USB clock control bit USBCKEN, second suspend mode control bit
SUSP2 and system clock selection bit SYSCLK. This register is also used to select which endpoint
FIFO is accessed by Endpoint FIFO Selection bits EPS2~EPS0. Further explanation on each of the
bits is given below:
UCC Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2~0
EPS2~EPS0: Endpoint FIFO selection
Unimplemented, read as “0”.
SYSCLK: System clock input selection
0: 12MHz clock is used
1: 6MHz clock is used
Unimplemented, read as “0”.
SUSP2: Suspend mode 2 control
0: optimized setting in suspend mode
1: test setting in suspend mode. The band-gap circuit is turned off.
USBCKEN: USB clock enable control
0: USB clock is disabled
1: USB clock is enabled
000: Endpoint 0 FIFO is selected
001: Endpoint 1 FIFO is selected
010: Endpoint 2 FIFO is selected
011: Endpoint 3 FIFO is selected
100: Endpoint 4 FIFO is selected
101: Endpoint 5 FIFO is selected
11x: reserved for further expansion and can not be used.
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 set to 0.
It is strongly recommended that this bit should be set to 0 when the USB interface is in
suspend mode. Otherwise, the unpredictable results will occur.
When the USB device receives the suspend signal sent from the USB host, the USB
clock enable control bit USBCKEN should be set to 0 to reduce the power consumption.
The EPS2~EPS0 bits are used to select which endpoint is to be accessed. If the selected
endpoint does not exist, the related functions are not available.
7
SYSCLK
R/W
6
0
5
10
SUSP2
R/W
4
0
USBCKEN
R/W
3
0
SPI to USB Bridge
EPS2
R/W
2
0
HT45B0K
EPS1
R/W
1
0
March 22, 2010
www.DataSheet4U.com
EPS0
R/W
0
0

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