Configure port to send logic, Computer Engineering

Assignment Help:

Configure port A for the lower 4 bits to be inputs and the upper 4 bits to be outputs. The program should chase a logic one from Pa4 -> Pa7, depending upon the condition of Pa0-Pa3 the speed of chase is increased.

Pa0  = 1  Slow Counter  
Pa1  = 1  Counter   
Pa2  = 1  Counter    
Pa3  = 1  Fast  Counter    
 
If all Pa0, Pa1, Pa2, Pa3 = 0 wait
 
The only major difference is the data direction i.e. this configures 4 input lines Pa0-Pa3 and 4 output lines Pa4-Pa7

Paddr
Bit7  Bit6  Bit5  Bit4  Bit3  Bit2  Bit1  Bit0
1  1  1  1  0  0  0  0
 
The full program is shown below

                  name first
padr          equ $0000
paddr        equ $0001
                 org $500
                 ldaa #$f0
                 staa paddr     set up half in and half out
loop0        ldaa #$10
                 staa padr     send data
                 jsr delay
                 ldaa #$20
                 staa padr     send data
                 jsr delay 
                ldaa #$40
                staa padr     send data
                jsr delay
                ldaa #$80
                staa padr     send data
                jsr delay
                jmp loop0
delay        ldab padr    ;get input from port a
                andb #$0f    ;mask of lower nibble only

                beq delay    ;repeat till selected
                ldab padr    ;get port a data again
                andb #$8    ; mask off bit 3 pa3
                bne loop3    ;if select go to loop3
                ldab padr    ;get port a data again
                andb #$4    ; mask off bit 2 pa2
                bne loop4    ;if select go to loop4
                ldab padr    ;get port a data again
                andb #$2    ; mask off bit 1 pa1
                bne loop5    ;if select go to loop5
                ldx #$ffff    ;assume pa0 is pressed load up x with ffff
                jmp loop1    ;carry on
loop2        ldx #$1    ;load up X with 1 fast
                jmp loop1    ;carry on
loop3        ldx #$f      ;load X with f
                jmp loop1
loop4       ldx #$ff    ;load x with ff
               jmp loop1
loop5      ldx #$fff    ;load x with fff slow
loop1      ldab #$1f    ;nested loop
loop6      decb
              bne loop6
              dex
             bne loop1    ;loop till zero
             rts               ;return back to main
             end


Related Discussions:- Configure port to send logic

Cg, raster scan display system

raster scan display system

Basic idea - learning decision trees, Basic idea: However in the above...

Basic idea: However in the above decision of tree which it is significant that there the "parents visiting" node came on the top of the tree. Whether we don't know exactly the

What is digital switch, Digital switch It is a device that handles digi...

Digital switch It is a device that handles digital signals formed at or passed by a telephone company's central office and sends them across the company's backbone network.

Conversion of decimal number 25.5 into binary number, Conversion of decimal...

Conversion of decimal number 25.5 into binary number Ans. There is integer part is 25 and fractional part is 0.5.  Firstly convert the integer part 25 in its equal to binary numb

Stack and queue, Describe queue? Ans:  It is a type of data structure ...

Describe queue? Ans:  It is a type of data structure in which the data are stored in and retrieved on a First in first out (FIFO) basis. It grows in the direction of increasin

Program that will blink as led, Take the last two digits of your UTCID. Thi...

Take the last two digits of your UTCID. This is your duty cycle in percent. If your duty cycle is less than 10%, add 30 to your number. Create an assembly program that runs on t

State about the machine language programs, State about the machine language...

State about the machine language programs The computer can run only machine language programs, one needs to translate above programs to machine language programs. To translate

What is a linked list, What is a linked list? Linked list: A linked l...

What is a linked list? Linked list: A linked list is a self referential structure which having a member field that point to the similar structure type. In simple term, a link

Important parameters for transmitting data, For this project, we hope to us...

For this project, we hope to use the basic idea of InfraRed (IR) communication for our television in ES103.  In ES103, we have a Sony large-screen television that we hope to commun

Explain concurrent sharing, Explain Concurrent Sharing Here a number of...

Explain Concurrent Sharing Here a number of programs that may share a file simultaneously. While this is the case, it is necessary to prevent mutual interference among them. Th

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd