Toshiba Libretto 50CT, User Manual

Page: 19 / 196

1.2 System Unit Block Diagram 1 Hardware Overview
1-6 Libretto 50CT/70CT Maintenance Manual
q
System Controller Gate Array
This gate array has the following functions:
•
Two PICs: 82C59 equivalent
•
Two UARTs:16550A equivalent (one SIO is used for SIR)
•
One PIT:82C54 equivalent
•
One RTC:T9934 equivalent
•
Two DMACs:82C37 equivalent
•
I/O port decode
•
SIO port control
•
Parallel (ECP) port control
•
Speaker control
•
Power supply microprocessor interface
•
PnP support
•
CPU control
−
SMI control
−
Clock speed control
•
Memory control
−
64-bit memory bus control
•
Video local bus control
−
64 to 32-bit, 32 to 64-bit data bus interface
•
Address latch control
−
Address conversion
−
Address latch
•
Hibernation control
•
Ring wake up control
•
PC card control
−
Memory card control
−
I/O card control
•
BIOS-ROM interface
•
Infrared port control
•
Sound control
q
Keyboard Controller (KBC)
This KBC includes: the keyboard scan controller and keyboard interface controller;
and controls: the internal keyboard, external keyboard, IPS and PS/2 mouse.