Sony DX4, 486DX Watchdog Timer Setting, Time Factor Time-Out Period Seconds, Time-Out Setting

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AR-B1474 User¡¦s Guide

4.4 WATCHDOG TIMER

This section describes how to use the Watchdog Timer, disabled, enabled, and trigger.

The AR-B1474 is equipped with a programmable time-out period watchdog timer. This watchdog timer can be enabled by your program. Once you have enabled the watchdog timer, the program should trigger it every time before it times out. If your program fails to trigger or disable this timer before it times out because of system hang- up, it will generate a reset signal to reset the system or generate the IRQ15 signal to tell your program that the watchdog is times out. The time-out period can be programmed to be 6 to 42 seconds.

Enable (D6, D7)

Time Factor (D0-D2)

Watchdog

Register

Write and Trigger

Time Base

Counter

and

Compartor

Watchdog

LED

Figure 4-1 Watchdog Block Diagram

RESET

IRQ15

4.4.1 Watchdog Timer Setting

The watchdog timer is a circuit that may be used from your program software to detect crashes or hang-ups. Whenever the watchdog timer is enabled, the LED will blink to indicate that the timer is counting. The watchdog timer is automatically disabled after reset.

Once you have enabled the watchdog timer, your program must trigger the watchdog timer every time before it times-out. After you trigger the watchdog timer, it will be set to zero and start to count again. If your program fails to trigger the watchdog timer before time-out, it will generate a reset pulse to reset the system or trigger the IRQ15 signal to tell your program that the watchdog is times out.

The factor of the watchdog timer time-out constant is approximately 6 seconds. The period for the watchdog timer time-out period is between 1 to 7 timer factors.

If you want to reset your system when watchdog times out, the following table listed the relation of timer factors between time-out period.

Time Factor	Time-Out Period (Seconds)
80H	3
81H	6
82H	12
83H	18
84H	24
85H	30
86H	36
87H	42

Table 4-1 Time-Out Setting

4-6

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Contents Industrial Grade 486DX/DX2/DX4 CPU Card Page Table of Contents Bios Console Specifications Placement & DimensionsMemory Banks & Programming RS-485 SSD Types Supported & IndexPreface Static Electricity Precautions OrganizationOverview IntroductionFeatures Packing ListSystem Controller DMA ControllerKeyboard Controller DMA ControllerInterrupt Controller Interrupt Controller1 I/O Port Address Map Hex Range DeviceI/O Port Address Map Timer Real-Time Clock and Non-Volatile RAMAddress Description Real-Time Clock & Non-Volatile RAMISA Bus Pin Assignment ISA Bus Pin AssignmentISA Bus Signal Description Name DescriptionSerial Port Receiver Buffer Register RBRTransmitter Holding Register THR DlabInterrupt Enable Register IER Interrupt Identification Register IIRLine Control Register LCR Modem Control Register MCRParallel Port Modem Status Register MSRDivisor Latch LS, MS Register AddressData Swapper Printer Status BufferPrinter Control Latch & Printer Control Swapper Setting UP the System OverviewSystem Setting RS-232 Connector DB1 & DB2Serial Port RS-485 Adapter Select JP3 & JP11Hard Disk IDE Connector CN1 Power Connector J5HDD Pin Assignment FDD Port Connector CN2 Parallel Port Connector CN3CN3 6 PC/104 Connector Pin PC/104 Connector Bus a & B CN6Pin PC/104 Connector Bus C & D CN4 PC/104 ISA Bus Signal Description IRQ 3-7, 9-12, 14CPU Setting AMD DX2-80 CPU Select JP1CPU Voltage Select JP2 AMD 4X CPU 5x86 Select JP15CPU Clock Setting CPU Clock Select JP6 & JP9Memory Setting Dram ConfigurationCache RAM Size Select JP8 SIMM1Keyboard Connector LED Header J1, J2 & J4Reset Header J7 Battery SettingExternal Speaker Header J3 CRT Display Type Select JP13Page Installation Utility Diskette PGM1474.EXE WD1474.EXE WP1474.EXE BU1474.EXE Display Error in PGF File Help to PGF FileEnable the Software Write Protect Disable the Software Write ProtectWrite Protect Function Hardware Write ProtectWatchdog Timer Watchdog Timer SettingTime-Out Setting Time Factor Time-Out Period SecondsWatchdog Timer Enabled Watchdog Timer TriggerWatchdog Timer Disabled Page Switch Setting Solid State DiskOverview 2 I/O Port Address Select SW1-1 & SW1-2SSD Firmware Address Select SW1-3 & SW1-4 DEVICE=C\DOS\EMM386.EXE X=C800-CFFFSSD Drive Number SW1-5 & SW1-6 Simulate 2 Disk DriveFlash Eprom Sram ROM Type Select SW1-7 & SW1-8 Disk Drive Name ArrangementJumper Setting SSD Bios Select JP7SSD Memory Type Setting M1 ~ M3 & JP5 ROM Disk InstallationSwitch and Jumper Setting UV Eprom 27CxxxUV Eprom 27CXXX Switch Setting Software Programming5V Large Flash 29FXXX Switch Setting Large Page 5V Flash Disk5V Flash 29CXXX & 28EEXXX Switch Setting Small Page 5V Flash ROM DiskUsing Tool Program Typing DOS CommandJumper Setting RAM DiskInstallation D.O.C Hardware SettingSSD Bios Setting JP7 Combination of ROM and RAM DiskSoftware Setting O.C. Setting SW1-8Page Bios Console Bios Setup OverviewStandard Cmos Setup Date & Time SetupFloppy Setup Hard Disk SetupAdvanced Cmos Setup IDE Block Mode Transfer IDE LBA ModeInternal Cache Memory ShadowAdvanced Chipset Setup Power Management Setting Password Password CheckingAuto Configuration with Optimal Setting Auto Configuration with Fail Safe SettingBios Exit Save Settings and ExitExit Without Saving Specifications BiosCPU PCBPage Placement & Dimensions PlacementDimensions Using Memory Bank Memory Banks & Programming RS-485CS1 CS0 SocketProgramming RS-485 Initialize COM portSend out one character Transmit Receive data Send out one character to COM1Page SSD Types Supported & Index SSD Types Supported10-2 Index Name Function