System Unit - Toshiba Satellite P20-25 Series Maintenance Manual

1.2 System Unit

1.2 System Unit
The system unit is composed of the following major components:
Processor
• Intel Desktop P4 up to 2.4GHZ or Northwood upgradable
– mPGA478 package CPU
– FSB533 Northwood CPU 2.53G/2.66G/2.8G w/o HT
– FSB533 Northwood CPU 3.06G w/HT
– FSB800 Northwood CPU 2.4G/2.6G/2.8G/3.0G/3.2G w/HT
System Logic
• Intel chipset MCH Springdale PE
• Integrated DRAM controller
• Accelerated Graphics Port (AGP) Interface
• Hub Interface to Intel ICH5
• Power Management Functions
Fixed Disk Interface
• Intel 82801 EB I/O Controller HUB5 (ICH5)
KBC/EC (Keyboard Controller/Embedded Controller)
• One PC87591 chip functions as both KBC and EC.
• KBC has the following functions:
– Scan controller to check status of keyboard matrix
– Interface controller between the keyboard scan controller and the
– Control of switching and simultaneous operation of the
• EC has the following functions:
– Power supply sequence control
– Thermal conditions control
– LEDs control
– Beep control
– Devices ON/OFF control
– FAN revolutions rate control
– General Input/Output port control
– Docker power supply control
– Battery capacity check
– Flash rewriting
– Detection of abnormal condition
– EC I/F
– I2C Communication
– EC access
Satellite P20-25 Series Maintenance Manual
system
accupoint/external PS/2 mouse and of the internal keyboard/external
PS/2 keyboard
1 Hardware Overview
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