Prestigio CAVALIERE 142, Техническое и сервисное руководство

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low-speed signaling.
The ICH4 supports 6 USB 2.0 ports. All six ports are high-speed, full-speed, and low-
speed capable. ICH4
’
s port-routing logic determines whether a USB port is controlled by
one of the UHCI controllers or by the EHCI controller. See Section 5.16,
“
USB UHCI
Controllers (D29:F0, F1 and F2) and Section 5.17,
“
USB EHCI Controller (D29:F7) for
details.
L AN Controller
The ICH4
’
s integrated LAN Controller includes a 32-bit PCI controller that provides
enhanced scatter-gather bus mastering capabilities and enables the LAN Controller to
perform high speed data transfers over the PCI bus. Its bus master capabilities enable the
component to process high-level commands and perform multiple operations; this lowers
processor utilization by off-loading communication tasks from the processor. Two large
transmit and receive FIFOs of 3 kB each help prevent data underruns and overruns while
waiting for bus accesses. This enables the integrated LAN Controller to transmit data with
minimum interframe spacing (IFS).
The LAN Controller can operate in either full duplex or half duplex mode. In full duplex
mode the LAN Controller adheres with the IEEE 802.3x Flow Control specification. Half
duplex performance is enhanced by a proprietary collision reduction mechanism. See
Section 5.2,
“
LAN Controller (B1:D8:F0)
”
on page 5-78 for details.
RTC
The ICH4 contains a Motorola* MC146818A-compatible real-time clock with 256 bytes of
battery-backed RAM. The real-time clock performs two key functions: keeping track of the
time of day and storing system data, even when the system is powered down. The RTC
operates on a 32.768 KHz crystal and a separate 3-V lithium battery that provides up to
seven years of protection.
The RTC also supports two lockable memory ranges. By setting bits in the configuration
space, two 8-byte ranges can be locked to read and write accesses. This prevents
unauthorized reading of passwords or other system security information.
The RTC also supports a date alarm that allows for scheduling a wake up event up to 30
days in advance, rather than just 24 hours in advance.
4.6 Clock Frequency Generator
The notebook utilizes the IMI CY28346 chip to supply the system clock needed to run the
computer. The following are the available clock frequencies:
System clock:
Clock generator IMI CY28346
suppo
rt:
- 66/100 MHz for Pentium III Mobile CPU
- 30/33 MHz for PCI device bus clock use
- 48 MHz for PIIX4M
- 14.318 MHz for PIIX4M refresh use
• 14.318 MHz XTAL for Clock Generator use
TECHNICAL SERVICE MANUAL Prestigio Cavaliere 142
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