Computer Systems Architecture / Microprocessors - Labs

profilebeoto01
elec_202_m6a2_lab.zip
Home>Computer Science homework help>Computer Systems Architecture / Microprocessors - Labs

M6A2 Lab Controlling the PC.docx

The objective of this lab is to control the hardware of a personal computer directly. A computer program called TONE.ASM (Attached) will be used to conduct this lab. This program is developed in assembly language.

Procedure

1. Download the program TONE.ASM (Attached). Assemble, link, and run. Hopefully, you will hear the speaker beep at a 1 KHz rate for a short period.

2. Adjust the INNER and OUTER values until the tone lasts for 5 seconds. How many loops are required? What is the speed of the processor on your system?

3. Readjust the INNER and OUTER values for tone duration of 0.25 seconds.

4. Modify the TONE.ASM program so that the 0.25-second 1 KHz tones plays five times, once each second. Hint: Use DOS INT 21H Function 2CH (Get Time) to read the system clock. Look for the seconds’ value to change. When it does, play the 0.25-second tone, then start watching the system clock again, waiting for the seconds to change again. Do this five times.

Here is some sample code for detecting when a new second has started:

<

The loop exits at the beginning of the new second. You will need to define NOW in the DATA portion of the program (NOW DB?).

5. Submit the final ASM file.

M6A2 Lab Missing sample code.GIF

tone.asm

;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