Q. Examine the features of a typical PC motherboard?
The purpose of this experiment is to examine the features of a typical PC motherboard, including:
- CPU and co-processor
- Memory
- I/O
- BIOS
- Interrupts
Procedure
Choose two chapters in the PDF for closer study. For each: 1) Do the "Questions/Activities" section and 2) Answer the questions in the Self Test section
Submit your findings.
Download copy of Program TONE.ASM: Generate a 1 KHz tone on the PC speaker for 5 seconds.
.MODEL SMALL
.DATA
;Note: You will have to adjust these values to get the 5 seconds.
;The current values give just over 1 second on a 1.3 GHz machine.
OUTER DW 4000 ;outer loop count
INNER DW 50000 ;inner loop count
.CODE
.STARTUP
CALL SPKRON ;turn speaker on
MOV CX,1190 ;divisor for 1 KHz tone
CALL LDTIMER ;set speaker frequency
CALL DELAY ;wait for chosen duration
CALL SPKROFF ;turn speaker off
.EXIT
SPKRON PROC NEAR
IN AL,61H ;read current state of port 61h
OR AL,3 ;set speaker control bits
OUT 61H,AL ;output new state
RET
SPKRON ENDP
SPKROFF PROC NEAR
IN AL,61H ;read current state of port 61h
AND AL,0FCH ;clear speaker control bits
OUT 61H,AL ;output new state
RET
SPKROFF ENDP
DELAY PROC NEAR
MOV DX,OUTER
WAIT1: MOV CX,INNER
WAIT2: NOP
NOP
NOP
NOP
LOOP WAIT2
DEC DX
JNZ WAIT1
RET
DELAY ENDP
;Note: Output frequency equals 1,190,000 divided by CX
LDTIMER PROC NEAR
MOV AL,0B6H ;timer 2 control word
OUT 43H,AL
MOV AL,CL ;output lower byte of count
OUT 42H,AL
MOV AL,CH ;output upper byte of count
OUT 42H,AL
RET
LDTIMER ENDP
END