; University of Illinois at Chicago, Dept. of Electrical and Computer Engineering
; ECE 367 -Microprocessor-Based Design
; Three Bit Counter
; Version 2, Aug 27, 2011
; By Robert A. Becker

; PAY ATTENTION TO THE ALIGNMENT BELOW
; Labels start in the first column  (left most column = colunm 1)
; OP CODES are at column 9
; COMMENTS follow a ";" symbol
; Blank lines are allowed (Makes the code more readable)

; Define symbolic constants
PortT	EQU	$240		;Define Register Locations
DDRT	EQU	$242
INITRG	EQU	$11
INITRM	EQU	$10
CLKSEL	EQU	$39
PLLCTL	EQU	$3A
CRGFLG	EQU	$37
SYNR	EQU	$34
REFDV	EQU	$35
COPCTL	EQU	$3C
TSCR1	EQU	$46
TSCR2	EQU	$4D
TIOS	EQU	$40
TCNT	EQU	$44
PortM EQU $250
DDRM EQU $252
SAVE EQU $60   ;created a variable to save my increment register because delay sub routine changes it.
TENSAVE EQU $5020
TC0	EQU	$50
TFLG1	EQU	$4E
;
; The ORG statment below would normally be followed by variable definitions
; There are no variables needed for this project.
; THIS IS THE BEGINNING SETUP CODE
;
	ORG	$3800		; Beginning of RAM for Variables
;
; The main code begins here. Note the START Label
;
	ORG	$4000		; Beginning of Flash EEPROM
START	LDS	#$3FCE		; Top of the Stack
	SEI			; Turn Off Interrupts
        MOVB	#$00, INITRG	; I/O and Control Registers Start at $0000
	MOVB	#$39, INITRM	; RAM ends at $3FFF
;
; We Need To Set Up The PLL So that the E-Clock = 24MHz
;
	BCLR CLKSEL,$80 ; disengage PLL from system
	BSET PLLCTL,$40 ; turn on PLL
	MOVB #$2,SYNR   ; set PLL multiplier
	MOVB #$0,REFDV  ; set  PLL divider
	NOP		; No OP
	NOP		; NO OP
PLP 	BRCLR CRGFLG,$08,PLP ; while (!(crg.crgflg.bit.lock==1))
	BSET CLKSEL,$80 ; engage PLL
;
;
;
	CLI		; Turn ON Interrupts
;
; End of  setup code. You will always need the above setup code for every experiment
;
;
;
;
;
;
;
;
;
;
;
;
;START CODING HERE____________________________________________________

	LDAA	#$FF	; Make PortT Outbound
	STAA	DDRT
  LDAA  #$FB  ; make pm2 inbound  but rest outbound
  STAA  DDRM

  LDAA #$3f
  STAA PortT
  LDAA #$03
  STAA PortM
  LDAA #$00
  STAA TENSAVE
  STAA PortM


THIS:

  BRSET SAVE, #$0A, TEN ; Branch to 'TEN' if save variable is incremented all the way to $10
  LDAB  #$00

HERE: BRSET PortM, #$04, HERE ; Branch if PM2 is SET (1) to HERE
 ;

 ; JSR  DELAY

   JSR DISPLAY
   BRA HERE
   BRA *
;  LDAB  #$00  ;initialize acc B to 0 to begin count in table
;  JSR   DISPLAY ;jump to sub routine 'display'
;THIS:         ;loop branch statement takes you here
  JSR DELAY

;
; We use some built-in timer functions to create an accurate delay
;
;
;
;
;
;
;
;
;
;
;
;------------------------------------------------
;GIVEN DELAY SUBROUTINE


DELAY 	PSHA			; Save accumulator A on the stack
	LDY	#03		; We will repeat this subroutine 3 times
	MOVB	#$90,TSCR1	; enable TCNT & fast flags clear
	MOVB	#$06,TSCR2 	; configure prescale factor to 64
	MOVB	#$01,TIOS	; enable OC0
	LDD	TCNT		; Get current TCNT value
AGAIN	ADDD	#37500		; start an output compare operation
	STD	TC0		; with 100 ms time delay
WAIT	BRCLR	TFLG1,$01,WAIT  ; Wait for TCNT to catch up
	LDD	TC0		; Get the value in TC0
	DBNE	Y,AGAIN		; 5 X 100ms = 1 sec
	PULA			; Pull A
	RTS       ;

;___________________________________________________________
;
;
;
;
;
;
;
;
;
;
;
;
;
;_____________________________________________________________
;displaylab3
DISPLAY:

  LDAA #$00
  STAA PortM, Y

  LDAB SAVE

  LDX   #TABLE   ;load table into x
  LDAA  B,X      ;load b'th element of table into a
  STAA  PortT,Y  ;display a in port t
  INCB           ;increment b for next run through loop
  LDAA  #$01      ;load bth element of table into a
  STAA  PortM,Y  ;display a in port m
;
  STAB  SAVE     ;save b in variable save before delay
;
  JSR   DELAY    ;Keep display on for a second with current uin digit
  JSR   DELAY

  LDAB  SAVE     ;transfer variable back into incrementing accumulator


  BRSET SAVE, #$0A, THIS ; Branch to 'this' if save variable is incremented all the way to $10,
  RTS
;__________________________________________________________________________


TEN
  LDAA #$00
  STAA PortM, Y
  LDAB TENSAVE

  LDX #TABLE
  LDAA  B, X
  STAA PortT, Y
  INCB
  STAB TENSAVE
  LDAA #$02
  STAA PortM, Y

  LDAB #$00
  STAB SAVE

  RTS







; End of counter code

  ;DISPLAY
;DISPLAY:
;  LDX   #TABLE   ;load table into x
;  LDAA  B,X      ;load b'th element of table into a
;  STAA  PortT,Y  ;display a in port t
;  INCB           ;increment b for next run through loop
;  LDAA  B,X      ;load bth element of table into a
;  STAA  PortM,Y  ;display a in port m
;
;  STAB  SAVE     ;save b in variable save before delay
;
;  JSR   DELAY    ;Keep display on for a second with current uin digit
;  JSR   DELAY

;  LDAB  SAVE     ;transfer variable back into incrementing accumulator
;
;  LDAA  #$00
;  STAA  PortT,Y  ;turn display off at the end of the program
;  STAA  PortM,Y  ;turn port m display off for break between uin units
  ;
  ;STAB  SAVE

  ;JSR   DELAY    ;Keep off for half second

  ;LDAB  SAVE

 ; INCB;           ;increment b again to get to next table entry

;  STAB SAVE

;  BRSET SAVE, #$12, THIS ; Branch to 'this' if save variable is incremented all the way to $12,

 ; JSR DISPLAY     ;back to the top of the loop
;table for uin
        ORG   $5000      ;memory location of table
TABLE:  DC.B  $06, $5b, $4f, $66, $6d, $7D, $07, $7F, $67, $3f
                  ;define table

; Define Power-On Reset Interrupt Vector

; AGAIN - OP CODES are at column 9

        ORG $FFFE ; $FFFE, $FFFF = Power-On Reset Int. Vector Location
        FDB START ; Specify instruction to execute on power up

; End of Interrupt code

        END        ; (Optional) End of source code