Toshiba T-Series T4850CT User manual

T4850CT
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1.1 Features
The Toshiba T4850CT is one of the lightest and most advanced portable computers available.
Utilizing advanced technology and high-speed components, the T4850CT offers excellent
color display legibility, battery operation and IBM PC/AT compatibility. The T4850CT
system unit consists of the following features:
❑Microprocessor
The Intel DX4TM Processor (referred to as DX4 in this manual) operates at 75 MHz,
3.3 Volts.
❑Math co-processor
The math co-processor is stored in the DX4.
❑Cache memory
16 KB of cache memory is stored in the DX4.
❑Disk storage
The T4850CT has an internal 2.5-inch 500 or 810 MB HDD. The 3.5-inch FDD
supports 2 HD (1.44 MB) floppy disks and 2DD (720 KB) floppy disks.
❑Memory
The T4850CT comes standard with 8 MB of CMOS Random Access Memory (RAM)
3.3 Volts. This includes 640 KB of conventional memory and 7,360 KB of extended
memory which can be utilized as expanded memory compatible with the Lotus/Intel/
Microsoft Expanded Memory Specifications (LIM-EMS).
❑TFT color LCD
The T4850CT has a high-resolution 10.4-inch full-color, Thin Film Transistor (TFT)
color LCD that displays 640 x 480 pixels.
The internal display controller supports VGA functions on the internal display and
SVGA functions on an external display.
❑Keyboard
An easy-to-use 82/84-key enhanced keyboard with full-size keys and standard spacing
is compatible with IBM standard software.

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T4850CT
❑Batteries
The T4850CT has three different batteries: a main battery, backup battery, and a Real
Time Clock (RTC) battery.
❑Status indicator panel
The status indicator panel is a liquid crystal display (LCD) panel which includes a
battery charge indicator and 11 icons indicating the system status.
❑Memory card slot
The optional memory card slot enables you to install a Toshiba optional memory card.
❑Personal Computer Memory Card International Association (PCMCIA) card slot
The two PCMCIA slots enable you to install an MiNC Toshiba card modem or other
industry-standard PCMCIA release 2.0 card.
❑Expansion port
The unique 150-pin expansion port allows you to connect the T4850CT to a Desk
Station IV.
❑PRT/FDD port
The Centronics-compatible parallel interface port serves two purposes: the port can
be used to connect a Centronics-compatible printer or an external 5.25-inch floppy
disk drive.
❑RS-232-C port
The RS-232-C port is a 9-pin serial interface port.
❑Mouse port
The 6-pin mouse port on the back supports an IBM PS/2 mouse.
❑Keyboard port
The 6-pin keyboard port on the back supports an IBM PS/2 keyboard.
❑Microsoft BallPoint mouse V2.0 with QuickPort connection (BPQP2)
The T4850CT has one BPQP2 port on the right.

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❑RGB port
The 15-pin RGB port on the back supports an external video display.
❑Audio ports
•Headphone, standard 3.5 mm diameter miniature stereo jack with speaker shut-off
switch.
Use a headphone with an impedance of 16Ω.
•Microphone, standard 3.5 mm diameter miniature monaural jack.

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T4850CT
The T4850CT Personal Computer is shown in Figure 1-1, and its system configuration is
illustrated in Figure 1-2.
Figure 1-1 T4850CT personal computer
Figure 1-2 T4850CT system unit configuration

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1.2 System Unit Block Diagram
Figure 1-3 is a block diagram of the T4850CT system unit.
Figure 1-3 T4850CT system board block diagram

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T4850CT
The system board shown in Figure 1-3 is composed of the following major components:
❑A DX4-75 CPU, which incorporates a math co-processor and 16 KB cache memory.
❑The following memory components:
Standard RAM: 8 MB, 32-bit data width (70 ns)
Cache memory: 16 KB (inside the DX4-75 CPU)
System, Video, 128 KB (96 KB are used), 8-bit data width
BIOS: A 1-Mbit flash ROM is used (150 ns).
This ROM contains Initial Reliability Test (IRT), Basic Input/
Output System (BIOS), and video BIOS.
Video RAM: 1 MB, 16-bit data width.
Two 256K x 16 bit chips are used.
Memory card: 4, 8, or 16 MB memory card can be installed.
32-bit data width.
❑Super Integration (SI) T9901, which stores the following components:
•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 I/O Controller
•One Printer Port Controller
•One Speaker Controller
❑Real Time Clock (RTC)
One T9934 chip is used (which has 128 of bytes memory). Fourteen bytes of memory
are used for the calendar and clock, and the remaining 114 bytes are used for system
configuration data.
❑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, external
keyboard port, PS/2 mouse port, and BPQP2 port.
❑VGA display controller: WD90C24A/A2 (208-pin) (3.3 volt operation)
This controller controls both internal and external VGA-compatible displays and
external SVGA-compatible displays with an Analog Digital Converter (DAC). The
controller can display data on the internal and external display simultaneously.

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❑Sound Controller
An AD1848 chip is used which controls the internal sound system.
❑The Clock Generator receives 14.31818 MHz (X1) and generates the following
frequencies:
•75 MHz for the CPU
•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 the RTC.
❑Gate Arrays
System Controller Gate Array
This gate array performs the 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
•Processing Speed Controller
•Data Bus Transfer
•Data Latch
•Suspend/Resume Controller

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T4850CT
Sub LCD Controller Gate Array
This gate array performs the following functions:
•Status Indicator Panel Controller
-LCD Segment Flashing Controller
•Internal Communication Controller
-KBC/Power Supply Micro Processor/Main CPU Communication
Controller
-KBC/Power Supply Micro Processor Interrupt Controller
IC Card Controller Gate Array
This gate array performs the following functions:
•IC Card Controller
-PCMCIA IC Card Controller
-Toshiba Modem Card Controller
•EEPROM (for security) Controller
-KBC-Security-EEPROM Communication Controller
•Others
-KBC Communication Controller
-Disable the PRT/FDD Port, HDD Access Controller
-EEPROM (for BIOS) Access Mode Controller
-Sound System Access Controller

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1.3 3.5-inch Floppy Disk Drive
The T4850CT 3.5-inch Floppy Disk Drive (FDD) is a thin, high-performance reliable drive
that supports 720-KB (formatted) 2DD and 1.44-MB (formatted) 2HD 3.5-inch floppy disks.
The FDD is shown in Figure 1-4, and its specifications are listed in Table 1-1.
Figure 1-4 3.5-inch FDD
Table 1-1 3.5-inch FDD specifications
Item 2 MB mode 1 MB mode
Storage capacity (KB)
Unformatted 2,000 1,000
Formatted 1,311 737
Number of heads 2 2
Number of cylinders 80 80
Access time (ms)
Track to track 3 3
Average 181 181
Head settling time 15 15
Recording track density (tpi) 135 135
Data transfer rate (Kbps) 500 250
Rotation speed (rpm) 300 300
Recording method Modified Frequency Modulation (MFM)

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T4850CT
1.4 2.5-inch Hard Disk Drive
The Hard Disk Drive (HDD) is a random access, nonvolatile storage device. It has a non-
removable 2.5-inch magnetic disk and mini-winchester type magnetic heads.
The T4850CT supports a 500 MB and 810 MB HDDs.
The HDD is shown in Figure 1-5, and its specifications are listed in Table 1-2.
Figure 1-5 2.5-inch HDD
Table 1-2 2.5-inch HDD specifications
500 MB 810 MB
MK2428FC DHAA-2540 DVAA-2810
Physical specifications
Formatted capacity (MB) 524.0 528.0 810.0
Disks 4 2 3
Heads 8 4 6
Cylinders 1,920 1,024 1,571
Bytes per sector (bps) 512 512 512
Recording method 1-7RLL 1-7RLL 1-7RLL
Performance specifications
Access time (average) 12 14.5 14.5
(track to track) 3 4 4
Maximum stroke 25 23.5 23.5
Rotation speed (rpm) 4,000 3,800 3,800
Data transfer rate (Mbps) 18.9 to 31.6 24.9 to 36.0 24.9 to 36.0
Power requirements
DC voltages (V) +5 only +5 only +5 only
Power (typical)
Seek (W) 3.6 2.0 2.8
Read (W) 2.8 2.8 2.8
Write (W) 2.8 2.8 2.8
Standby mode
(Spin only) (W) 0.4 0.4 0.4
Sleep mode
(Motor off) (W) 0.15 0.4 0.4
Spin-up mode (mA) 780 940 940
Items