AR-B1474 User¡¦s Guide

(3) Data Swapper

The system microprocessor can read the contents of the printer’ s Data Latch through the Data Swapper by reading the Data Swapper address.

(4) Printer Status Buffer

The system microprocessor can read the printer status by reading the address of the Printer Status Buffer. The bit definitions are described as follows:

7 6 5 4 3 2 1 0 X X X

-ERROR SLCT PE -ACK -BUSY

Figure 2-2 Printer Status Buffer

NOTE: X presents not used.

Bit 7: This signal may become active during data entry, when the printer is off-line during printing, or when the print head is changing position or in an error state. When Bit 7 is active, the printer is busy and can not accept data.

Bit 6: This bit represents the current state of the printer’ s ACK signal. A 0 means the printer has received the character and is ready to accept another. Normally, this signal will be active for approximately 5 microseconds before receiving a BUSY message stops.

Bit 5: A 1 means the printer has detected the end of the paper.

Bit 4: A 1 means the printer is selected.

Bit 3: A 0 means the printer has encountered an error condition.

(5) Printer Control Latch & Printer Control Swapper

The system microprocessor can read the contents of the printer control latch by reading the address of printer control swapper. Bit definitions are as follows:

7

 

6

5

4

3

2

 

1

 

0

 

 

X

 

X

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

STROBE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AUTO FD XT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INIT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SLDC IN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IRQ ENABLE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DIR(write only)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2-3 Bit’ s Definition

NOTE: X presents not used.

Bit 5: Direction control bit. When logic 1, the output buffers in the parallel port are disabled allowing data driven from external sources to be read; when logic 0, they work as a printer port. This bit is write only.

Bit 4: A 1 in this position allows an interrupt to occur when ACK changes from low state to high state.

Bit 3: A 1 in this bit position selects the printer.

Bit 2: A 0 starts the printer (50 microseconds pulse, minimum).

Bit 1: A 1 causes the printer to line-feed after a line is printed.

Bit 0: A 0.5 microsecond minimum highly active pulse clocks data into the printer. Valid data must be present for a minimum of 0.5 microseconds before and after the strobe pulse.

2-10

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Sony DX4, 486DX, AR-B1474 manual Data Swapper, Printer Status Buffer, Printer Control Latch & Printer Control Swapper
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DX4, AR-B1474, 486DX specifications

The Sony 486DX, AR-B1474, and DX4 are notable examples of advanced computing technologies from the early to mid-1990s, a time when personal computers were rapidly evolving to meet increasing user demands. These systems played a pivotal role in shaping the landscape of modern computing.

The Sony 486DX is built around the popular Intel 80486 microprocessor, which was a significant step up from its predecessor, the 386. The 486DX featured a 32-bit architecture and introduced integrated cache memory, which greatly enhanced data processing speeds and overall system performance. Operating at clock speeds typically ranging from 25 to 100 MHz, the 486DX models provided a solid foundation for running more sophisticated software applications and advanced games of the era.

Accompanying the 486DX was the AR-B1474 motherboard, designed to maximize the potential of the 486 architecture. This motherboard featured support for up to 512 KB of level 2 cache memory, further boosting performance for data-heavy tasks. The AR-B1474 also included extensive connectivity options, with ISA slots for legacy devices, as well as support for EISA, making it compatible with a wide range of hardware peripherals. This versatility made the AR-B1474 a popular choice among builders of custom desktop PCs during its time.

The DX4, another significant milestone, built upon the 486 architecture by introducing a clock-doubling technique. By effectively allowing the processor to perform operations at up to three times its base clock speed (typically 75 or 100 MHz), the DX4 could handle even more demanding applications, thereby providing users with significant performance improvements without requiring a complete overhaul of their systems.

Both the 486DX and DX4 processors facilitated advancements in multimedia capabilities, with improved graphics rendering and audio performance that supported CD-ROMs and early gaming technologies. This made them particularly appealing to consumers looking for a versatile machine for both work and entertainment.

Overall, the combination of the Sony 486DX, AR-B1474 motherboard, and DX4 processor exemplifies a significant chapter in computing history, showcasing how hardware advancements seamlessly integrated with user needs for performance and flexibility. As these technologies laid the groundwork for future innovations, they remain noteworthy for their contributions to the evolution of personal computing.
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