30 Mobile Intel
®
945GM Express Chipset
Development Kit User’s Manual
Theory of Operation
3.4.2.8 Serial, IrDA
The SMSC SIO incorporates a serial port, and IrDA (Infrared), as well as general purpose IOs
(GPIO). The serial port connector is provided at J2A2A, and the IrDA transceiver is located at
U4A1. The IrDA transceiver on Intel
®
945GM Express Chipset supports both SIR (slow IR) and
CIR (Consumer IR). The option to select between the two is supported through software and GPIO
pin on the SIO.
3.4.2.9 BIOS Firmware Hub (FWH)
The 8 Mbit Flash device used on the Intel
®
945GM Express Chipset to store system and video
BIOS as well as an Intel Random Number Generator (RNG) is a socketed E82802AC8 a 32-pin
PLCC package. The reference designator location of the FWH device is U8G1. The BIOS can be
upgraded using an MS-DOS* based utility and is addressable on the LPC bus off of the ICH7-M.
3.4.2.10 System Management Controller (SMC)/Keyboard Controller
The Hitachi* H8S/2104V serves as both SMC and KBC for the platform. The SMC/KBC
controller supports two PS/2 ports, battery monitoring and charging, EMA support, wake/runtime
SCI events, and power sequencing control. The two PS/2 ports on the Intel
®
945GM Express
Chipset are for legacy keyboard and mouse. The keyboard plugs into the bottom jack and the
mouse plugs into the top jack at J1A1. Scan matrix keyboards can be supported via an optional
connector at J9E1.
3.4.2.11 Clocks
The Intel
®
945GM Express Chipset board uses a CK-410M and CK-SSCD compatible solution.
The CK-SSCD solution offers improved EMI performance by spreading the radiated clock
emissions over a wider spectrum than a single frequency. This is accomplished while controlling
the clock frequency deviation such that system performance is not compromised. The FSB
frequency is determined from decoding the processor BSEL[2:0] pin settings.
3.4.2.12 Real Time Clock
An on-board battery at BT5H1 maintains power to the real time clock (RTC) when in a mechanical
off state. A CR2032 battery is installed on the Intel
®
945GM Express Chipset development kit.
3.4.2.13 Thermal Monitoring
The processor has a thermal diode for temperature monitoring. The SMC thermal monitoring
device will throttle the processor if it becomes hot. If the temperature of the processor rises too
high, the SMC will alternately blink the CAPS lock and NUM lock LEDs on the board, and the
board will shut down.
3.4.3 System I/O and Connector Summary
The evaluation board provides extensive I/O capability in the form of internal connectors and
headers as detailed by the following list. For detailed information on these connectors and headers,
please refer to “Hardware Reference” on page 39.
• One (x16) PCI Express* connector
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