AR-B1474 User¡¦s Guide

Example 1: Select the 10th bank of the MEM1 on the AR-B1474. The AR-B1474 is using 27C020 (256K*8), and the base port is &H210.

100 base_port=&H210

110 OUT base_port+0,&H59

Example 2: Select the 40th bank of MEM3 on the AR-B1474. The AR-B1474 is using 27C040 (512K*8), and the base port is &H390.

200 base_port=&H390

210 OUT base_port+0,&HD7

9.2 PROGRAMMING RS-485

The majority communicative operation of the RS-485 is in the same of the RS-232. When the RS-485 proceeds the transmission which needs control the TXC signal, and the installing steps are as follows:

Step 1: Enable TXC

Step 2: Send out data

Step 3: Waiting for data empty

Step 4: Disable TXC

NOTE: Please refer to the section of the “Serial Port” in the chapter “System Control” for the detail description of the COM port’ s register.

(1) Initialize COM port

Step 1: Initialize COM port in the receiver interrupt mode, and /or transmitter interrupt mode. (All of the communication protocol buses of the RS-485 are in the same.)

Step 2: Disable TXC (transmitter control), the bit 0 of the address of offset+4 just sets “0” .

NOTE: Control the AR-B1474 CPU card’ s DTR signal to the RS-485’ s TXC communication.

(2) Send out one character (Transmit)

Step 1: Enable TXC signal, and the bit 0 of the address of offset+4 just sets “1” .

Step 2: Send out the data. (Write this character to the offset+0 of the current COM port address)

Step 3: Wait for the buffer’ s data empty. Check transmitter holding register (THRE, bit 5 of the address of offset+5), and transmitter shift register (TSRE, bit 6 of the address of offset+5) are all sets must be “0” .

Step 4: Disabled TXC signal, and the bit 0 of the address of offset+4 sets “0”

9-2

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Sony DX4, 486DX, AR-B1474 manual Programming RS-485, Initialize COM port, Send out one character Transmit
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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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