Sony 486DX, DX4, AR-B1474 Watchdog Timer Enabled, Watchdog Timer Trigger, Watchdog Timer Disabled

Page 37

AR-B1474 User¡¦s Guide

If you want to generate IRQ15 signal to warn your program when watchdog times out, the following table listed the relation of timer factors between time-out period.

Time Factor

Time-Out Period (Seconds)

0C0H

3

0C1H

6

0C2H

12

0C3H

18

0C4H

24

0C5H

30

0C6H

36

0C7H

42

Table 4-2 Time-Out Setting

NOTE: 1. If you program the watchdog to generate IRQ15 signal when it times out, you should initial IRQ15 interrupt vector and enable the second interrupt controller (8259 PIC) in order to enable CPU to process this interrupt. An interrupt service routine is required too.

2.Before you initial the interrupt vector of IRQ15 and enable the PIC, please enable the watchdog timer previously, otherwise the watchdog timer will generate an interrupt at the time watchdog timer is enabled.

4.4.2Watchdog Timer Enabled

To enable the watchdog timer, you have to output a byte of timer factor to the watchdog register whose address is Base Port+4. The following is a BASICA program which demonstrates how to enable the watchdog timer and set the time-out period at 24 seconds.

1000

REM Points to command register

1010

WD_REG% = BASE_PORT% + 4

1020

REM Timer factor = 84H (or 0C4H)

1030

TIMER_FACTOR% = %H84

1040

REM Output factor to watchdog register

1050

OUT WD_REG%, TIMER_FACTOR%

 

.,etc.

4.4.3 Watchdog Timer Trigger

After you enable the watchdog timer, your program must write the same factor as enabling to the watchdog register at least once every time-out period to its previous setting. You can change the time-out period by writing another timer factor to the watchdog register at any time, and you must trigger the watchdog before the new time-out period in next trigger. Below is a BASICA program which demonstrates how to trigger the watchdog timer:

2000

REM Points to command register

2010

WD_REG% = BASE_PORT% + 4

2020

REM Timer factor = 84H (or 0C4H)

2030

TIMER_FACTOR% = &H84

2040

REM Output factor to watchdog register

2050

OUT WD_REG%, TIMER_FACTOR%

 

.,etc.

4.4.4 Watchdog Timer Disabled

To disable the watchdog timer, simply write a 00H to the watchdog register.

3000

REM Points to command register

3010

WD_REG% = BASE_PORT% + 4

3020

REM Timer factor = 0

3030

TIMER_FACTOR% = 0

3040

REM Output factor to watchdog register

3050

OUT WD_REG%, TIMER_FACTOR%

 

., etc.

4-7

Page 36 Page 38
Image 37
Page 36 Page 38
Contents Industrial Grade 486DX/DX2/DX4 CPU Card Page Table of Contents Specifications Placement & Dimensions Bios ConsoleMemory Banks & Programming RS-485 SSD Types Supported & IndexPreface Organization Static Electricity PrecautionsIntroduction OverviewPacking List FeaturesDMA Controller System ControllerKeyboard Controller DMA ControllerInterrupt Controller Interrupt ControllerHex Range Device 1 I/O Port Address MapI/O Port Address Map Real-Time Clock and Non-Volatile RAM TimerAddress Description Real-Time Clock & Non-Volatile RAMISA Bus Pin Assignment ISA Bus Pin AssignmentName Description ISA Bus Signal DescriptionReceiver Buffer Register RBR Serial PortTransmitter Holding Register THR DlabInterrupt Identification Register IIR Interrupt Enable Register IERLine Control Register LCR Modem Control Register MCRModem Status Register MSR Parallel PortDivisor Latch LS, MS Register AddressPrinter Status Buffer Data SwapperPrinter Control Latch & Printer Control Swapper Overview Setting UP the SystemRS-232 Connector DB1 & DB2 System SettingSerial Port RS-485 Adapter Select JP3 & JP11Power Connector J5 Hard Disk IDE Connector CN1HDD Pin Assignment Parallel Port Connector CN3 FDD Port Connector CN2CN3 Pin PC/104 Connector Bus a & B CN6 6 PC/104 ConnectorPin PC/104 Connector Bus C & D CN4 IRQ 3-7, 9-12, 14 PC/104 ISA Bus Signal DescriptionAMD DX2-80 CPU Select JP1 CPU SettingCPU Voltage Select JP2 AMD 4X CPU 5x86 Select JP15CPU Clock Select JP6 & JP9 CPU Clock SettingDram Configuration Memory SettingCache RAM Size Select JP8 SIMM1LED Header J1, J2 & J4 Keyboard ConnectorBattery Setting Reset Header J7External Speaker Header J3 CRT Display Type Select JP13Page Installation PGM1474.EXE Utility DisketteWP1474.EXE WD1474.EXEBU1474.EXE Help to PGF File Display Error in PGF FileDisable the Software Write Protect Enable the Software Write ProtectWrite Protect Function Hardware Write ProtectWatchdog Timer Setting Watchdog TimerTime-Out Setting Time Factor Time-Out Period SecondsWatchdog Timer Trigger Watchdog Timer EnabledWatchdog Timer Disabled Page Solid State Disk Switch Setting2 I/O Port Address Select SW1-1 & SW1-2 OverviewSSD Firmware Address Select SW1-3 & SW1-4 DEVICE=C\DOS\EMM386.EXE X=C800-CFFFSimulate 2 Disk Drive SSD Drive Number SW1-5 & SW1-6Flash Eprom Sram Disk Drive Name Arrangement ROM Type Select SW1-7 & SW1-8SSD Bios Select JP7 Jumper SettingROM Disk Installation SSD Memory Type Setting M1 ~ M3 & JP5Switch and Jumper Setting UV Eprom 27CxxxSoftware Programming UV Eprom 27CXXX Switch SettingLarge Page 5V Flash Disk 5V Large Flash 29FXXX Switch SettingSmall Page 5V Flash ROM Disk 5V Flash 29CXXX & 28EEXXX Switch SettingTyping DOS Command Using Tool ProgramRAM Disk Jumper SettingHardware Setting Installation D.O.CSSD Bios Setting JP7 Combination of ROM and RAM DiskO.C. Setting SW1-8 Software SettingPage Bios Setup Overview Bios ConsoleDate & Time Setup Standard Cmos SetupFloppy Setup Hard Disk SetupAdvanced Cmos Setup IDE LBA Mode IDE Block Mode TransferInternal Cache Memory ShadowAdvanced Chipset Setup Power Management Password Checking Setting PasswordAuto Configuration with Optimal Setting Auto Configuration with Fail Safe SettingSave Settings and Exit Bios ExitExit Without Saving Bios SpecificationsCPU PCBPage Placement Placement & DimensionsDimensions Memory Banks & Programming RS-485 Using Memory BankCS1 CS0 SocketInitialize COM port Programming RS-485Send out one character Transmit Send out one character to COM1 Receive dataPage SSD Types Supported SSD Types Supported & Index10-2 Name Function Index

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.
Top Page Image Contents