Toshiba T3400CT - CPU and Memory Components; System Controller and Interface Chips

T3400/T3400CT Maintenance Manual
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The T3400/T3400CT system board includes the following major components:
❑ i486SX-33 CPU
❑ Super Integration (SI) T9901 Gate Array (GA), which houses the following:
• Two Direct Memory Access Controllers (DMAC): 82C37
• Two Programmable Interrupt Controllers (PIC): 82C59
• One Programmable Interval Timer (PIT): 82C54
• One Floppy Disk Controller (FDC): TC8565
• One Serial Input/Output Controller (SIO): TC8570
• One Variable Frequency Oscillator (VFO): TC8568
• One Input/Output (I/O) Controller
• One Printer Port Controller
• One Speaker Controller
❑ RTC
One T9934 chip with 128 bytes of memory is used. Fourteen bytes of memory are
used for the calendar and clock, and the remaining 114 bytes for system configura-
tion data.
OSC (X2) generates 32.768 KHz for the RTC.
❑ Keyboard Controller (KBC)
One M37452M4 chip is used. This KBC includes the keyboard scan controller and
keyboard interface controller. The KBC controls the internal keyboard, Accupoint
(pointer control stick), external keyboard, and PS/2 mouse.
❑ The following memories:
Standard RAM: 4 MB
Cache memory: 8 KB (inside CPU)
BIOS ROM: 128 KB (96 KB are used)
This ROM contains Initial Reliability Test (IRT), Basic
Input Output System (BIOS), and video BIOS.
Video RAM: 256 KB
Optional cards can be used to expand memory to a maximum of 20 MB.
❑
VGA display controller (WD90C24)
This controller controls the internal VGA display and external SVGA- compatible
display.