Toshiba T4500 User Manual page 9

The T4600 and T4600C system board shown in Figure 1-5 is composed of the following major
components:
An i486SL-33 CPU
One Intel 82360SL
This component is super set with the i486SL microprocessor and stores the following CPU
peripheral components:
Two DMACs 8237 equivalent
Two PICs
Two PITs
Two SIOs
One RTC
One EPP
One super integration (SI) T9920
The components include the following:
One FDC
One VFO
One speaker controller
A Keyboard Controller (KBC): M37452M4
This KBC includes the keyboard scan controller and keyboard interface controller. The
KBC controls the internal keyboard, external keyboard port, PS/2 mouse port, and ball point
quick port.
The following memories:
Standard RAM:
Cache memory: 8 KB (inside CPU)
BIOS ROM:
Video RAM:
Optional memory cards expand memory to a maximum of 20 MB.
VGA display controller: WD90C26A (144-pin) (3.3 volt operation)
This controller controls internal and external VGA compatible displays. It can display the
internal and external displays at the same time.
8259 equivalent
8254 equivalent (T4600 and T4600C uses one PIT.)
16450 equivalent (T4600 and T4600C uses one SIO.)
MC146818AF equivalent
(Enhanced Parallel Port) controller
TC8565 equivalent
TC8568 equivalent
4 MB
128 KB (96 KB are used)
This Read Only Memory (ROM) contains Initial Reliability Test (IRT),
Basic Input/Output System (BIOS), and video BIOS.
512 KB
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