Elevator Simulation

I came to school this morning (Saturday, 4/9/16) hoping that someone might be able to let me into the Microprocessors lab at some point today. After working on some other homework near the entrance for about an hour, I spotted my TA walking in. Praise God!

So I worked on the project for about 5 hours and I think I've got it to a good place to call finished. There are some points I'm not going to get, but the complexity of those requirements is something I'm not about to spend another 10 hours on.

What I completed today:

• Incorporated the Buzzer with an additional "include" file.
• Floors numbers displaying correctly on LCD, no matter which floor they are called from.
• LEDs are all mapped and turning on and off when they should.
• Added a second version of the "Readkeys" subroutine that loops finitely rather than in-finitely so that a keypress can interrupt the delay routine.
• Macro to write a blank line to the LCD.
• "Arrive" subroutine that fills in a gap in the logical of arriving at a floor (convenient, eh?).

Added a video to the details section! Enjoy!

Yesterday, Thursday 4/7/16, I was in the lab from 12:00-2:30. It was not exceedingly successful in terms of getting closer to the finished project. I spent a lot of time trying to make the LCD display the correct floor number, regardless of which floor form which the user is starting the motion. Unfortunately, I ran out of time as I was getting close - I think ;). I actually think that I have the flow of the program complete. All of the major loops and subroutines (and returns) appear to be functioning as I intend them to.

I still don't know if this thing is supposed to be done by Tuesday, 4/12/16, but I can't imagine anyone in class is going to be finished if the lab isn't opened between now and then.

Todos:

• Correct floor displayed on LCD
• Incorporate buzzer
• Write open/close door routine
  • The skeleton and calls to these subroutines already exist.
  • I need to add a call to WRT_STRING in each
• Turn on correct LEDs at the correct time

I was in the lab today from 11:30-4:00. Made quite a bit of progress on the logical flow and organization of the project.

One of the big milestones was learning how to use additional files as libraries. I broke the code up into 4 or 5 separate files based on functionality. This was as simple as creating a text document with the .inc suffix, right-clicking on the "Sources" directory in the project tree, and adding the text document. The code was modified as such:

;***************
;Header....
;
;***************
...
   INCLUDE 'newText.inc'
...
   Code

I also worked out a lot of the logical flow. There is essentially a forever loop in the main function. In its ready state, it is waiting for keypad input. A series of compare instructions test which subroutine to jump to based on which key is pressed. The current draft of this loop is shown below:

MAIN
        
    ;Waiting for Input
    JSR     READKEYS
    
    STAA    LAST_KY        
    
    CMPA    #OPEN
    BEQ     B1
    
    CMPA    #CLOSE
    BEQ     B2
       
    CMPA    #EXT_1
    BGE     B3
    
    CMPA    #INT_1
    BEQ     B4
    
    CMPA    #INT_2
    BEQ     B4
    
    CMPA    #INT_3
    BEQ     B4
    
    CMPA    #INT_4
    BEQ     B4
 
B1 JSR     OPEN_DOOR
    BRA     MAIN
    
B2 JSR     CLOSE_DOOR
    BRA     MAIN    
    
B3 JSR     COME
    BRA     MAIN   
    
B4  JSR     GOTO    
    BRA     MAIN

This thing is supposed to be done by next Tuesday, but with only one more lab day available to us before then, I'm not sure how far we are going to get. I plan on working in the lab on Thursday, 4/7/16, 12:00-2:00.

To write a string to the LCD on the HCS12, I wrote the following bit of assembly:

;main bit of program running up here
;               ....  ........              
;               ....  ........
                LDX   #NEX_FLR        ;load X with string pointer
                LDY   #NEX_LEN        ;load Y with string length
                JSR   WRT_STRING      ;jump to WRT_STRING sub
                

WRT_STRING					
DISP		  
		LDAA  X               ;put the value at X in A
		JSR   DATWRT4         ;sub to write the character
		JSR   DELAY           ;required delay for LCD
		INX                   ;next letter in the string
		DBNE  Y, DISP         ;decrement string count and repeat
		RTS                   ;once string is all printed, return


NEX_LEN EQU     11                    ;string length
NEX_FLR FCB     'Next Floor '         ;string contents

I have uploaded a number of files associated with this project. We have been given source assembly code to get us going with interfacing the HCS12 with the LCD and keypad on the Dragon12 board.

I spent some time in the lab on Thursday, 3/31/16 during Ayaz's office hours. I was able to get the LCD to display keypad digits and characters. I am working on better merging the LCD and keypad source code. I hope to work some sort of library structure into the mix to improve the organization of the project.

My next opportunity for lab time will be Tuesday, 4/5/16, 11:30-4:00.

To-do:

• Define memory structure
• Explore library organization
• Define LED and keypad assignments
• Create all necessary strings for LCD display