TREK-755/TREK-756 User Manual
54
Appendix A Programming the Watchdog Timer
A.1 Programming the Watchdog Timer
To program the watchdog timer, you must write a program which writes
to I/O port address 440 (hex). The output data is a time interval value.
The value range is from 01 (hex) to 3F (hex), and the related time interval
is from 1 to 63 seconds.
Data Time Interval
01
1 sec.
02
2 sec.
03
3 sec.
04
4 sec.
3F
63 sec.
After data entry, your program must refresh the watchdog timer by rewrit-
ing the I/O port 440 (hex) while simultaneously setting it. When you want
to disable the watchdog timer, your program should read I/O port 440
(hex).
The following example shows how you might program the watchdog
timer.
;-----------------------------------------------------------------------------------
; Enter the extended function mode, interruptible double-write
;-----------------------------------------------------------------------------------
MOV DX,2EH
MOV AL,87H
OUT DX,AL
OUT DX,AL
;-----------------------------------------------------------------------------
; Configure logical device 8, configuration register CRF6
;-----------------------------------------------------------------------------
MOV DX,2EH
MOV AL,07H; point to Logical Device Number Reg.
Summary of Contents for TREK-755
Page 1: ...TREK 755 TREK 756 Vehicle Mounted Computer with 10 4 12 1 TFT LCD User Manual...
Page 12: ...TREK 755 TREK 756 User Manual xii...
Page 20: ...TREK 755 TREK 756 User Manual 8...
Page 28: ...TREK 755 TREK 756 User Manual 16...
Page 48: ...TREK 755 TREK 756 User Manual 36...
Page 53: ...2 CHAPTER 8 Audio Introduction Installation of Audio Driver...
Page 55: ...CHAPTER 9 USB 2 0 This chapter describes how to install the USB 2 0 driver...