Typical Pit Counter Value Load Subroutine; Typical Pit Counter Read Subroutine - Intel iSBC 86/14 Hardware Reference Manual

PROGRAMMING INFORMATION
Table 3-6. Typical PIT Counter Value Load Subroutine
LOADO LOADS COUNTER 0 FROM CX, CH IS MSB, CL IS LSB. USES-D,E:
DESTROYS-AL. CX MUST BE LOADED PRIOR TO CALLING THE ROUTINE.
PUBLIC LOADO
LOADO:
MOV AL,CL :GET LSB
OUT ODOH,AL
MOV
AL,CH
:GET MSB
OUT
ODOH,AL
RET
END
Table 3-7. Typical PIT Counter Read Subroutine
READl READS COUNTER
1
ON-THE-FLY INTO CX, MSB IN CH, LSB IN CL:
DESTROYS-AL,CX.
PUBLIC
READl:
MOV
OUT
IN
MOV
IN
MOV
RET
END
READl
AL,4OH
OD6H,AL
AL,OD2H
CL,AL
AL,OD2H
CH,AL
;MODE WORD FOR LATCHING COUNTER 1
VALUE
;LSB OF COUNTER
;MSB OF COUNTER
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