;christmas chain
;(C)2005 by wek   http://www.efton.sk
;use freely; please let me know to xmas-at-efton.sk if you use it or modify it
;
;LED chain is driven by 2x74LS164 in a cascade,
;LEDs connected directly (no resistors) anodes to 74LS164 outputs,
;  cathodes to GND
;for "properly" connected LEDs to shift registers (cathodes to outputs,
;  anodes through resistor to VCC), invert data in the shiftout routine (IntT0)
;for latched shift registers, drive latch after shifting out all data
;  by end of IntT0
;CLOCK of 74LS164 connected to P1.7, DATA to P1.5
;XTAL=22.1184MHz, for cca 11MHz xtal reload 80h into th0 in IntT0
;$SET(SPI) to use hardware SPI on P89V51RD2
;
;for adding "effects":
;- insert jump to "effect" routine into AlgosTab
;- at the beginning of "effect" routine check IntTim1, return if nonzero
;- if IntTim1 is zero
;  - set IntTim1 to constant timing one "step" of the "effect"
;  - if effect initialisation is required, do it when AlgoTim=0FFh
;  - perform the "effect" by modifying Data0 and Data1
;  - decrement AlgoTim
;- return




        $SET(SPI)


T2CON   EQU 0c8h
T2MOD   EQU 0c9h
TH2     EQU 0CDh
TL2     EQU 0CCh
TR2     EQU 0CAh  ;SFR bit (in T2CON)
RCAP2L  EQU 0CAh
RCAP2H  EQU 0CBh



LED     EQU   P3.6   ;this LED flashes wildly indicating operation



Data0   EQU    20h
Data1   EQU    21h
IntFlag EQU    22h.0

Rnd     EQU    30h   ;8 bytes
IntTim1 EQU    38h
AlgoNo  EQU    39h
AlgoTim EQU    3Ah   ;2 bytes (?) ;counter for how many times an algo should be executed


Stack   EQU    40h


        USING 0

CSEG
        org 0
        ljmp Start

        org 0Bh
        ljmp IntT0


;------------------- INIT ---------------------
        org 30h
Start:
        mov  sp,#Stack-1
        mov  tmod,#20h        ; Timer1 autoreload 8bit (baud generator), Timer0 in 13bit mode
        mov  th1,#-1 ;#0feh       ; 115200 at 22.1184MHz
        mov  pcon,#80h
        mov  scon,#72h       ; 8 bit UART mode, but with the "no RI if no stop bit" feature activated
        mov  tcon,#30h       ; run timers
        mov  t2con,#0        ;autoreload mode, osc/12
;        mov  ie,#82h         ; only timer0 interrupt enabled

        mov  P1,#0F9h       
        mov  P3,#0DFh       



        mov  r3,#2*5
LampTX1:
        djnz r0,LampTX1
        djnz r1,LampTX1
        cpl  LED
        djnz r3,LampTX1



        mov  AlgoNo,#0
        mov  AlgoTim,#0FFh

        mov  Data0,#12h
        mov  Data1,#45h
;--- init SPI
        $IF(SPI)
        mov  0D5h,#01110001b
        $ENDIF

        setb tr0     ;hmmmm... this was already enabled in tcon...
        setb tr1
        setb et0
        setb ea




Loop:
        call Randomize

        
        jnb  ri,RIW1
        cpl  LED
        mov  Data0,sbuf
        clr  ri
RIW1:



;         call  Run1
        call  CallAlgos

;        call LongDelay

        jmp  Loop

        


Stop:   sjmp Stop


CallAlgos:
       mov   a,AlgoTim
       jnz   CAX1
       dec   AlgoTim
       inc   AlgoNo
       mov   a,AlgoNo
       add   a,#'0'
       jnb   ti,$
       clr   ti
       mov   sbuf,a
CAX1:
       mov   a,AlgoNo
       add   a,AlgoNo
       add   a,AlgoNo
       mov   dptr,#AlgosTab
       jmp   @a+dptr

AlgosTab:
       ljmp  Run1
       ljmp  Run2
       ljmp  Run3
       ljmp  Run4
       ljmp  Run4a
       ljmp  Run5
Restart:  ;the last in AlgosTab
       mov   AlgoNo,0
       ret




;---------- interrupt

IntT0:
;        mov  th0,#128   ;this constant determines the overall speed - uncomment if xtal<22MHz

        push psw
        push acc

        setb IntFlag
        mov  a,IntTim1
        jz   IntTX1
        dec  IntTim1
IntTX1:
        cpl  LED


        $IF(SPI)
        mov  a,Data0
        ;cpl  a         ;if LEDs are connected "properly"
        mov  86h,a
Wait1:
        mov  a,0AAh
        jnb  acc.7,Wait1
        anl  0AAh,#01111111B

        mov  a,Data1
        ;cpl  a         ;if LEDs are connected "properly"
        mov  86h,a
Wait2:
        mov  a,0AAh
        jnb  acc.7,Wait2
        anl  0AAh,#01111111B

        $ELSE
        push b
        push ar2
        
        mov  a,Data0
        ;cpl  a         ;if LEDs are connected "properly"
        mov  b,#8
Loop1:  clr  P1.7
        rrc  a
        mov  P1.5,c
;        call Delay
        setb P1.7
;        call Delay
        djnz b,Loop1

        mov  a,Data1
        ;cpl  a         ;if LEDs are connected "properly"
        mov  b,#8
Loop2:  clr  P1.7
        rrc  a
        mov  P1.5,c
;        call Delay
        setb P1.7
;        call Delay
        djnz b,Loop2

        pop ar2
        pop b

        $ENDIF

        ;place triggering the latch here, if latched shiftregister used

        pop  acc
        pop  psw
        reti
;--------------- utils ---------
Delay:
;        jnb ri,Delay
;        clr ri
;        ret


        mov  r2,#2
Delay1:
        djnz r2,Delay1
        ret


LongDelay:
        mov  r2,#80
        mov  r4,#0
LDelay1:
        djnz r4,LDelay1

        djnz r2,LDelay1
        ret



Randomize:
            mov   a,RND+3
            rr    a
            rr    a
            xrl   a,RND+2
            rr    a
            rr    a
            rr    a
            rr    a
            xrl   a,RND
            rr    a
            xrl   a,RND
            xrl   a,#1
            rrc   a
            mov   a,RND
            rlc   a
            mov   RND,a
            mov   a,RND+1
            rlc   a
            mov   RND+1,a
            mov   a,RND+2
            rlc   a
            mov   RND+2,a
            mov   a,RND+3
            rlc   a
            mov   RND+3,a
            
            mov   a,RND+7
            anl   a,#11101010b
            mov   c,p
            rlc   a
            xrl   a,RND+4
            rrc   a
            mov   a,RND+7
            rrc   a
            mov   RND+7,a
            mov   a,RND+6
            rrc   a
            mov   RND+6,a
            mov   a,RND+5
            rrc   a
            mov   RND+5,a
            mov   a,RND+4
            rrc   a
            mov   RND+4,a
            
            ret


;----- Data modification algos

Run1:                   ;random running from end to beginning
;         jnb  IntFlag,IWX1
;         clr  IntFlag
         mov  a,IntTim1
         jnz  Run1X1
         mov  IntTim1,#20    ;speed
         mov  a,Rnd+7
         anl  a,#7
         clr  c
         jnz  Run1X2
         setb c
Run1X2:  mov  a,Data0
         orl  a,Data1
         jnz  Run1X3
         setb c
Run1X3:  mov  a,Data0
         jnb  acc.0,Run1X4
         clr  c
Run1X4:  mov  a,Data0
         rlc  a
         mov  Data0,a
         mov  a,Data1
         rlc  a
         mov  Data1,a
         dec  AlgoTim
Run1X1:
         ret


Run2:                   ;random running from beginning to end
         mov  a,IntTim1
         jnz  Run2X1
         mov  IntTim1,#20    ;speed
         mov  a,Rnd+7
         anl  a,#7
         clr  c
         jnz  Run2X2
         setb c
Run2X2:  mov  a,Data0
         orl  a,Data1
         jnz  Run2X3
         setb c
Run2X3:  mov  a,Data1
         jnb  acc.7,Run2X4
         clr  c
Run2X4:  mov  a,Data1
         rrc  a
         mov  Data1,a
         mov  a,Data0
         rrc  a
         mov  Data0,a
         dec  AlgoTim
Run2X1:
         ret


Run3:                   ;1:1 flash
         mov  a,IntTim1
         jnz  Run3X1
         mov  IntTim1,#40    ;speed
         mov  a,AlgoTim
         inc  a
         jnz  Run3X2
         mov  Data0,#55h
         mov  Data1,#55h
         mov  AlgoTim,#100   ;short down this mode - it's too long and boring
Run3X2:
         xrl  Data0,#0FFh
         xrl  Data1,#0FFh
         dec  AlgoTim
Run3X1:
         ret



Run4:    mov  a,IntTim1        ;KIT - KnightRider
         jnz  Run4X1
         mov  IntTim1,#16

         mov  a,AlgoTim
         mov  b,#14
         div  ab
         mov  a,b
         mov  r2,a
         add  a,#Run4T1-Run4X2
         movc a,@a+pc
Run4X2:
         mov  Data0,a

         mov  a,r2
         add  a,#Run4T2-Run4X3
         movc a,@a+pc
Run4X3:
         mov  Data1,a

         dec  AlgoTim
Run4X1:
         ret
Run4T1:  db   80h,40h,20h,10h,08h,04h,02h
         db   01h,02h,04h,08h,10h,20h,40h

Run4T2:  db   01h,02h,04h,08h,10h,20h,40h
         db   80h,40h,20h,10h,08h,04h,02h



Run4a:   mov  a,IntTim1        ;KIT - KnightRider - 2
         jnz  Run4aX1
         mov  IntTim1,#16

         mov  a,AlgoTim
         mov  b,#22
         div  ab
         mov  a,b
         mov  r2,a
         add  a,#Run4aT1-Run4aX2
         movc a,@a+pc
Run4aX2:
         mov  Data0,a

         mov  a,r2
         add  a,#Run4aT2-Run4aX3
         movc a,@a+pc
Run4aX3:
         mov  Data1,a

         dec  AlgoTim
Run4aX1:
         ret
Run4aT2: db   80h,40h,20h,10h,08h,04h,02h
         db   01h,02h,04h,08h,10h,08h,04h,02h
         db   01h,02h,04h,08h,10h,20h,40h

Run4aT1: db   01h,02h,04h,08h,10h,20h,40h
         db   80h,40h,20h,10h,08h,10h,20h,40h
         db   80h,40h,20h,10h,08h,04h,02h



Run5:                   ;ping-pong
         mov  a,IntTim1
         jnz  Run5X1
         mov  IntTim1,#15    ;speed
         mov  a,AlgoTim
         inc  a
         jnz  Run5X2
         mov  Data0,#01h
         mov  Data1,#00h
         sjmp Run5X3
Run5X2:
         mov  a,AlgoTim
         jnb  acc.4,Run5X4     ;determine the movement direction
         clr  c
         mov  a,Data0
         rlc  a
         mov  Data0,a
         mov  a,Data1
         rlc  a
         jc   Run5X3       ;not to loose the "ball" if it would "fall over the edge"
         mov  Data1,a
         sjmp Run5X3
Run5X4:
         clr  c
         mov  a,Data1
         rrc  a
         mov  Data1,a
         mov  a,Data0
         rrc  a
         jc   Run5X3       ;not to loose the "ball" if it would "fall over the edge"
         mov  Data0,a
Run5X3:
         dec  AlgoTim
Run5X1:
         ret




;------------------ THAT'S ALL, FOLKS! -------------------



        end