Intermec PEN*KEY 6100, Руководство программиста

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SECTION 6 Conversions and Interfaces
PEN*KEY
R
6100 Computer Programmer’s Reference Guide 6-97
Timer and Real-Time Clock Services: Interrupt
1Ah
INT 1Ah, Function AH = 00h: Read System Timer Ticks
BIOS
Retrieves the values from the BIOS data areas 40:6Eh (high word) and 40:6Ch
(low word). The value returned is the total number of clock ticks since midnight
of system timer channel 0. Clock ticks occur 18.2 times per second and are proĆ
cessed by INT 08h. Interrupts are disabled while the timer tick is read to preĆ
vent update during access to the memory locations. The timer overflow flag, reĆ
turned in AL, is reset to zero when this function is executed.
On Entry: AH = 00h
On Return:
CX = High word of system timer tick count
DX = Low word of system timer tick count
AL = Timer overflow flag
0 if day has not rolled over since last read
1 if timer value has exceeded 24 hours
INT 1Ah, Function AH = 01h: Set System Timer Ticks
BIOS
Sets the BIOS data values located at 40:6Ch and 40:6Eh to the data contained in
CX and DX, respectively. It thereby sets the system timer tick count. Execution
of this function clears the timer overflow flag at location 40:70h.
On Entry:
AH = 01h
CX = High byte of the system timer tick count
DX = Low byte of the system timer tick count
On Return:
None
INT 1Ah, Function AH = 02h: Read the Real-Time Clock Time
BIOS
Reads the hour, minute, second, and Daylight Savings option data from the
CMOS RAM area of the MC 146818. Must verify that the updateĆinĆprogress bit
is zero and disable interrupts before accessing the CMOS data.
On Entry:
AH =02h
On Return:
CH = Hours in BCD (0ć23)
CL = Minutes in BCD (0ć59)
DH = Seconds in BCD (0ć59)
DL = Daylight Savings Time option
0 = No Daylight Savings Time
1 = Daylight Savings Time
6. Conversions and
Interfaces