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VGA display controller: WD90C24A (208-pin)
This controller controls internal and external VGA compatible display and external
SVGA compatible display with Analog Digital Converter (DAC). It can display data
on the internal and external display at the same time and operates at 3.3 volts.
.
Sound Controller
One AD1848 chip is used. The AD1848 controls the internal sound system.
Clock Generator receives 14.31818 MHz (X1) and generates the following frequen-
cies:
• 25 MHz for the CPU (CPU operates 50MHz[T4700CS/T4700CT] or
75MHz [T4800CT])
• 14.7456 MHz for the COM
• 24 MHz for the FDC and VFO
• 16 MHz is used for GA
• 14.31818 MHz for WD90C24A (for VGA)
OSC (X3) generates 32.768 KHz for RTC.
Gate Array
System Controller Gate Array
This gate array has following functions:
• CPU Controller
- SMI Controller
- CPU Clock Controller
• Memory Controller
- DRAM Controller
- Compatible Bus Interface Controller
• Bus Controller
- Compatible Bus Interface Controller
- Compatible Access Controller
- DMAC Controller
- I/O Controller
• Address Latch Controller
- 32-Bit to 16-Bit Controller
- Address Latch
- DMA Address Generator
- Refresh Address Generator
• I/O Register
- Compatible I/O Port Register
- Saving the data of the Register (in resume) Controller
- Toshiba Special Register
T4700CS, T4700CT, T4800CT
1-7
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