FabiaTech FB2701, Руководство пользователя

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Watchdog Timer Enabled
To enable the watchdog timer, you have to output a byte of timer factor to the
watchdog register whose address is 2eh and data port is 2fH. The following is a Demo
program, which demonstrates how to enable the watchdog timer and set the time-
out period at 28 seconds.
;------------------------------------------------------------------------------------------
; Enter the extended function mode
;------------------------------------------------------------------------------------------
outportb (0x2e,0x87); // Enter to extended function mode
outportb(0x2e,0x01);
outportb(0x2e,0x55);
outportb(0x2e,0x55);
;--------------------------------------------------------------------------------------------------------------
; Logical device 7, configuration registers Index 72h-Bit 7, 73H (LSB)/74H (MSB)
;--------------------------------------------------------------------------------------------------------------
outportb(0x2e,0x72); // Index 72h- Time and Watchdog Register
outportb(0x2f,0xc0); // Set Bit 7 is 1: Second and Bit6: Enabled Watchdog.
//outportb(0x2f,0x40); // Set Bit 7 is 0: Minute.
outportb(0x2e,0x74); // Set Timer Value counter1 0100~FF00 (MSB)
outportb(0x2f,0x00);
outportb(0x2e,0x73);
// Set Timer Value counter0 0001~00FF (LSB)
outportb(0x2f,0x28); // Set timeout interval as 28seconds and start counting
;------------------------------------------------------------------------------------------
; Exit the extended function mode
;------------------------------------------------------------------------------------------
outportb(0x2e,0x02); // Set Timer Value counter0 0001~00FF (LSB)
outportb(0x2f,0x02); // Set timeout interval as 28seconds and start counting
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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.
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Watchdog Timer Disabled
To disable the watchdog timer, simply write a 00H to the watchdog register.
;--------------------------------------------------------------------------------------------------------------
; Logical device 7, configuration registers Index 72h Bit 6
;--------------------------------------------------------------------------------------------------------------
outportb(0x2e,0x72);
// Index 72h- Time and Watchdog Register
outportb(0x2f,0x80); // Set Bit6 to 0 Disabled Watchdog.