;****************************************************************
; 68705P3 6-Sided Die						*
;****************************************************************
; "Rolls" a six sided die with a display composed of seven	*
; RGB LEDs. "18-Bit-ish" RGB is generated through software	*
; 3-Channel PWM over PortC 0->2.				*
; Results can be weighted by modifying Die_WeightTable.		*
;								*
; Written by: Osman Celimli					*
;****************************************************************
	PROCESSOR 68705
	INCDIR	    "C:\MC68705"
	INCLUDE     "68705P3.asm"

	ORG HARDWARE_BASE	; Padding for programmer
	dc.b $FF		; format restrictions (2048x8)
;****************************************************************
; RAM Layout							*
;****************************************************************
	ORG RAM_START
PWM_RGBState	ds.b 1		; 0= Switch Diode, Reactivate All
				; 1= Deactivate All
				; 2= Deactivate 2
				; 3= Deactivate 1
PWM_RGBTTable	ds.b 4		; 0=All Off,1=Last Off,2=Second Off,3=First Off,4=All On
PWM_RGBDelays	ds.b 4		; Note that entry 0 is PWM_RGBState, since the value
PWM_DiodeSelect	ds.b 1		; can be assumed to be zero when this is required.
				; This means all accesses to this are shifted+1
PWM_DeadTime	ds.b 7
PWM_BrightL	ds.b 7
PWM_BrightM	ds.b 7
PWM_BrightF	ds.b 7		; PWM Settings for each element delay, should sum to 64

PWM_Active	ds.b 7		; Number of active RGB Triads in one PWM Sweep
PWM_MiddleOff	ds.b 7
PWM_FirstOff	ds.b 7		; Order Diodes are shut off, Last not needed, assumed 0

Disp_Retrace	ds.b 1		; Pulled high every full display update (~60Hz)
FrameCounter	ds.b 1

DieDisp_RBright ds.b 7
DieDisp_GBright ds.b 7
DieDisp_BBright ds.b 7		; Software modifiable die-display structure

Attract_Dir	ds.b 1

SetD_Num	ds.b 1
SetD_R		ds.b 1
SetD_G		ds.b 1
SetD_B		ds.b 1
SetD_Active	ds.b 1
SetD_TempX	ds.b 1
SetD_TSlot	ds.b 1
SetD_DeadDelay	ds.b 1
SetD_SortRGB	ds.b 3
SetD_PortSet	ds.b 3		; RGB Setting Routine Temps

Die_Rolled	ds.b 1
Die_Rolling	ds.b 1
Die_RollDel	ds.b 1
Die_RollDelAcc	ds.b 1
Die_RollDone	ds.b 1
Die_Face	ds.b 1

;All these shared redefines are here since we're getting
;dangerously close to the system stack here...
;
; So we need to make sure there's just a little overhead
; for the IRQ handler (5 bytes) plus 3 extra.
;Die_TempX	ds.b 1
Die_TempX	EQU (SetD_TempX)
;Die_TempY	ds.b 1
Die_TempY	EQU (SetD_TSlot)
;Attract_Del	ds.b 1
Attract_Del	EQU (Die_RollDel)

	ECHO "RAM Left: ",(RAM_END-*)
;****************************************************************
; ZeroPage EPROM						*
;								*
;								*
;****************************************************************
	ORG EPROM_ZEROPAGE
;****************************************************************
; RGB Diode Transition Table					*
;****************************************************************
PWM_Diode_SelO dc.b %01111110,%01111101,%01111011,%01110111,%01101111,%01011111,%00111111
PWM_Diode_SelA dc.b %11111110,%11111101,%11111011,%11110111,%11101111,%11011111,%10111111
;****************************************************************
; Timer IRQ							*
;****************************************************************
; Note- Frequency is obtained by a 
; ((4Mhz Source Clock / 4 Pre-Prescaler) / 32 Prescaler) / 64 Max SW PWM Period
; ~488Hz IRQ For RGB Diode Select, ~70Hz for all 7 RGB Diode Updates
; Accounting for delays in this IRQ, it's probably more like ~60Hz...
;
; This isn't the most accurate PWM ever, but it's stable and the three
; software channels are good enough for color mixing on the diodes.
Timer_IRQ	SUBROUTINE
	LDA #%00000101
	STA Timer_Control	; Clear IRQ

	LDX PWM_RGBState
	LDA PWM_RGBTTable-1,X
	STA PortC_Data		; Set RGB State

	DEX
	bmi .SelectNextDiode
	STX PWM_RGBState
	LDA PWM_RGBDelays,X
	STA Timer_Data		; Set next PWM Interval
	rti			; if single RGB PWM period isn't finished
.SelectNextDiode
	LDX PWM_DiodeSelect
	DEX
	bpl .SetPortBState
	INC Disp_Retrace
	LDX #6
.SetPortBState
	STX PWM_DiodeSelect
	LDA PortB_Data
	ORA PWM_Diode_SelO,X
	AND PWM_Diode_SelA,X
	STA PortB_Data		; Set up Diode Select

	clr PWM_RGBTTable	; Last triad set assumed all off
	LDA PWM_MiddleOff,X	; Note the shifts present here. See variable descs.
	STA PWM_RGBTTable+1
	LDA PWM_FirstOff,X
	STA PWM_RGBTTable+2

	LDA PWM_DeadTime,X
	STA PWM_RGBDelays
	LDA PWM_BrightL,X
	STA PWM_RGBDelays+1
	LDA PWM_BrightM,X
	STA PWM_RGBDelays+2
	LDA PWM_BrightF,X
	STA PWM_RGBDelays+3
	LDA PWM_Active,X
	STA PWM_RGBState	; Restart PWM State, Set Number of Active Triads
	TAX
	LDA PWM_RGBTTable,X
	STA PortC_Data		; Turn on RGB
	LDA PWM_RGBDelays,X
	STA Timer_Data		; Copy next PWM Interval
	rti



	ECHO "Zero Page ROM Left: ",(EPROM_USER-*)
;****************************************************************
; Main User EPROM						*
;								*
;								*
;****************************************************************
	ORG EPROM_USER
;****************************************************************
; Start								*
;****************************************************************
Start		SUBROUTINE
	jsr AttractMode
	jsr RollTrigger
	jsr RollDie
	jsr PostRollPhase

.WaitforRetrace
	LDA Disp_Retrace
	beq .WaitforRetrace
	clr Disp_Retrace
	LDX #0
.CopyNewBrights
	STX SetD_Num
	LDA DieDisp_RBright,X
	STA SetD_R
	LDA DieDisp_GBright,X
	STA SetD_G
	LDA DieDisp_BBright,X
	STA SetD_B
	jsr SetDiodeColor
	LDX SetD_Num
	INX
	CPX #7			; Go in the opposite order of the Display
	bne .CopyNewBrights	; IRQ to minimize delays...
	INC FrameCounter	; This has to be done outside the PWM IRQ, or else we get an
	bra Start		; unusually long VBlank.
;****************************************************************
; Post-Roll Color Phasing					*
;****************************************************************
PostRollPhase	SUBROUTINE
	LDA Die_RollDone
	bne .DelayforAttract
	rts
.DelayforAttract
	DEC Attract_Del
	beq .SetAttractMode
	rts
.SetAttractMode
	LDA #1
	STA Attract_Dir
	clr Die_Rolled		; Re-enable attract Mode (but scale down RGB first...)
	clr Die_RollDone
	clr Die_Rolling
	rts
;****************************************************************
; Check for Roll Trigger					*
;****************************************************************
RollTrigger	SUBROUTINE
	LDA PortA_Data
	AND #$F
	CMP #$F
	bne .PortALow
	rts
.PortALow
	LDX FrameCounter
	LDA Die_WeightTable,X
	STA Die_Face
	LDA #1
	STA Die_Rolled		; Kill Attract Mode
	STA Die_Rolling
	LDA #240
	STA Attract_Del		; Reset Attract Delay
	clr Die_RollDel
	clr Die_RollDelAcc
	clr Die_RollDone	; Clear Roll delay accumulator and roll completion flag.
	rts
;****************************************************************
; Roll								*
;****************************************************************
RollDie		SUBROUTINE
	LDA Die_Rolling
	bne .DoRolling
	rts
.DoRolling
	DEC Die_RollDel
	bmi .RollDelayExpire
	rts
.RollDelayExpire
	LDA Die_RollDelAcc
	ADD #3
	STA Die_RollDelAcc
	STA Die_RollDel
	CMP #50
	bpl .DelayAccumulated
	sei
	LDA PortB_Data
	EOR #128
	STA PortB_Data		; Click! Goes the Piezo.
	cli
	LDA Die_Face
	INC
	CMP #6
	bne .NoFaceRollover
	LDA #0
.NoFaceRollover
	STA Die_Face
	jmp SetDieFace
.DelayAccumulated
	LDA #1
	STA Die_RollDone
	clr Die_Rolling
	rts
;****************************************************************
; Set Die Image							*
;****************************************************************
SetDieFace	SUBROUTINE
; A=Die Number to Display
	TAX
	LDA DieRGB_Offsets,X
	STA Die_TempX
	LDX #0
.CopyDiePlanes
	STX Die_TempY
	LDX Die_TempX
	LDA DieRGB_Face1,X
	INX
	STX Die_TempX
	LDX Die_TempY
	STA DieDisp_RBright,X
	INX
	CPX #21
	bne .CopyDiePlanes
	rts

; Note
; PCB Layout is like this :
;	0 1 2
;	  3
;	4 5 6
; With the piezo at the top left.
; However, the LEDs are wired backwards to the PortB outputs, so
; in terms of array indecies consider things to be the following:
;	6 5 4
;	  3
;	2 1 0
; Where each element has an RGB setting from 0-63.
; All the RGB settings below are stored in planarish format, 7x8bppR,G,B
DieRGB_Face1	dc.b 0,0,0
		dc.b 63
		dc.b 0,0,0
		dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0
		dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0	; Red One-Center
DieRGB_Face2	dc.b 0,0,63
		dc.b 0
		dc.b 63,0,0
		dc.b 0,0,63
		dc.b 0
		dc.b 63,0,0
		dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0	; Yellow Top-Left and Bottom-Right
DieRGB_Face3	dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0
		dc.b 0,0,63
		dc.b 63
		dc.b 63,0,0
		dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0	; Green Diagonal Tri-Stripe
DieRGB_Face4	dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0
		dc.b 63,0,63
		dc.b 0
		dc.b 63,0,63
		dc.b 63,0,63
		dc.b 0
		dc.b 63,0,63	; Turquoise Four-Square
DieRGB_Face5	dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0
		dc.b 0,0,0
		dc.b 0
		dc.b 0,0,0
		dc.b 63,0,63
		dc.b 63
		dc.b 63,0,63	; Blue Five-Cross
DieRGB_Face6	dc.b 63,63,63
		dc.b 0
		dc.b 63,63,63
		dc.b 63,63,63
		dc.b 0
		dc.b 63,63,63
		dc.b 63,63,63
		dc.b 0
		dc.b 63,63,63	; White Six-Doubleline

DieRGB_Offsets	dc.b 0,21,42,63,84,105
;****************************************************************
; Startup Initialization					*
;****************************************************************
MC68705_Init	SUBROUTINE
	sei
	RSP
; First, Zero all of RAM.
	LDX #(RAM_END-RAM_START)
.RAMClear
	clr RAM_START,X
	DEX
	bpl .RAMClear

; Now initialize the ports...
	LDA #0
	STA PortA_DataDirection ; Port A is input (Switches)
	LDA #$FF
	STA PortB_DataDirection ; Both Port B (Piezo, RGB Cathode Select) and
	STA PortC_DataDirection ; and Port C (RGB, RUN) are output
	LDA #00
	STA PortB_Data
	STA PortC_Data		; and are init'd to zero.


	LDA #7
	STA PWM_RGBTTable+3	; Force highest triad table to be all on.
	LDX #6
.Init_RGB
	LDA #%0001
	STA PWM_MiddleOff,X
	LDA #%0011
	STA PWM_FirstOff,X
	LDA #34
	STA PWM_DeadTime,X
	LDA #3
	STA PWM_Active,X	; All Active
	LDA #10
	STA PWM_BrightL,X
	STA PWM_BrightM,X
	STA PWM_BrightF,X	; Initialize PWM Settings
	DEX
	bpl .Init_RGB

	LDA #63
	STA Timer_Data		; Set down counter
	LDA #%00001101
	STA Timer_Control	; Unmask IRQ, Reset Prescale, Start Timer.
	cli
	jmp Start
;****************************************************************
; Set RGB Diode Color						*
; Colors in SetD_R,SetD_G,Set_B (0-63).				*
; Diode to Adjust in SetD_Num (0-6).				*
;****************************************************************
SetDiodeColor	SUBROUTINE
	LDX #2			; First cap the raw RGB values
	LDA #3
	STA SetD_Active
.CapRGBSettings
	LDA SetD_R,X
	CMP DiodeColorHiCap,X
	bmi .CapRGBSettingLo
	LDA DiodeColorHiCap,X
	STA SetD_R,X
	bra .CapRGBSettingNext
.CapRGBSettingLo
	LDA SetD_R,X
	CMP DiodeColorLoCap,X
	bpl .CapRGBSettingNext
	clr SetD_R,X
	DEC SetD_Active		; If < 1, Decrease the number of available traids
.CapRGBSettingNext
	DEX
	bpl .CapRGBSettings	; RGB Values are all capped, now ensure =/=

	LDX #2
.CheckRGBEquality
	LDA SetD_R,X
	beq .ValueNotEqual
	CPX #0
	beq .CheckGreen
	CMP SetD_R
	beq .AdjustOffset
.CheckGreen
	CPX #1
	beq .CheckBlue
	CMP SetD_G
	beq .AdjustOffset
.CheckBlue
	CPX #2
	beq .ValueNotEqual
	CMP SetD_B
	bne .ValueNotEqual
.AdjustOffset
	INC SetD_R,X
	bra .CheckRGBEquality
.ValueNotEqual
	DEX			; I feel like there should be a better way to do this...
	bpl .CheckRGBEquality	; But I can't think of anything right now that doesn't use two indexes.
				; Anyway, now we need to find the sorted order of these things...

	LDX #2
.ClearSortList
	clr SetD_SortRGB,X
	clr SetD_PortSet,X
	DEX
	bpl .ClearSortList

	LDX #2
.CompareRGBOrder
	LDA SetD_R,X
	clr SetD_TSlot
	CPX #0
	beq .CompareGreen
	CMP SetD_R
	bpl .CompareGreen
	INC SetD_TSlot
.CompareGreen
	CPX #1
	beq .CompareBlue
	CMP SetD_G
	bpl .CompareBlue
	INC SetD_TSlot
.CompareBlue
	CPX #2
	beq .SetRGBOrder
	CMP SetD_B
	bpl .SetRGBOrder
	INC SetD_TSlot
.SetRGBOrder
	STX SetD_TempX
	LDX SetD_TSlot
.CheckSlot
	LDA SetD_PortSet,X
	beq .CopySorted
	INX
	CPX #2
	bne .CheckSlot
.CopySorted
	STX SetD_TSlot
	LDX SetD_TempX
	LDA SetD_R,X
	LDX SetD_TSlot
	STA SetD_SortRGB,X
	LDX SetD_TempX
	LDA DiodeColorOff,X
	LDX SetD_TSlot
	STA SetD_PortSet,X

	LDX SetD_TempX
	DEX
	bpl .CompareRGBOrder	; Now everything is sorted, so let's generate the port outputs

	LDA SetD_PortSet
	AND SetD_PortSet + 1
	AND SetD_PortSet + 2
	STA SetD_PortSet
	LDA SetD_PortSet + 1
	AND SetD_PortSet + 2
	STA SetD_PortSet + 1	; Then the RGB Delays

	LDA #63
	SUB SetD_SortRGB
	STA SetD_DeadDelay
	LDA SetD_SortRGB
	SUB SetD_SortRGB + 1
	STA SetD_SortRGB
	LDA SetD_SortRGB + 1
	SUB SetD_SortRGB + 2
	STA SetD_SortRGB + 1

	LDX SetD_Num		; Set things in PWM-Land
	LDA SetD_SortRGB
.WaitforSafeInterval
	CPX PWM_DiodeSelect
	beq .WaitforSafeInterval
	sei			; Hopefully this will be quick enough...
	STA PWM_BrightL,X
	LDA SetD_SortRGB + 1
	STA PWM_BrightM,X
	LDA SetD_SortRGB + 2
	STA PWM_BrightF,X
	LDA SetD_DeadDelay
	STA PWM_DeadTime,X	; First the delays...

	LDA SetD_Active
	STA PWM_Active,X	; Then the active triads...

	LDA SetD_PortSet + 1
	STA PWM_MiddleOff,X
	LDA SetD_PortSet + 2
	STA PWM_FirstOff,X	; Then the port settings
	cli			; Done!
	rts

DiodeColorOff	dc.b %0110,%0101,%0011 ; PBGR
DiodeColorHiCap dc.b 62,61,60
DiodeColorLoCap dc.b 1,1,1
;****************************************************************
; Boot Attract Mode						*
;****************************************************************
AttractMode	SUBROUTINE
	LDA Die_Rolled
	beq .DoRGBStrobes
	rts
.DoRGBStrobes
	LDA Attract_Dir
	beq .ScaleUp00

.ScaleDown00
	LDX #0
.ScaleDown01
	LDA DieDisp_RBright,X
	bne .ScaleDown02
	INX
	CPX #21
	bne .ScaleDown01
	clr Attract_Dir
	rts
.ScaleDown02
	DEC DieDisp_RBright,X
	rts

.ScaleUp00
	LDX #0
.ScaleUp01
	LDA DieDisp_RBright,X
	CMP #63
	bne .ScaleUp02
	INX
	CPX #21
	bne .ScaleUp01
	INC Attract_Dir
	rts
.ScaleUp02
	INC DieDisp_RBright,X
	rts
;****************************************************************
; Dummy IRQ							*
;****************************************************************
Dummy_IRQ	SUBROUTINE
	rti
;****************************************************************
; WeightTable							*
;								*
;****************************************************************
; You can modify this to "weight" the die rolls.
; Right now the distribution is marginally leaning towards 2-3-4-5
Die_WeightTable		dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5,1
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5,2
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5,3
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5,4
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5
			dc.b 0,1,2,3,4,5


	ECHO "User EROM Left: ",(EPROM_MASKREG-*)
;****************************************************************
; Mask Option Regs						*
;****************************************************************
	ORG EPROM_MASKREG
; Crystal Clock, Software Timer
; Internal Clock Timer Source, External Timer Disable
; and Prescale setting of /32.
MaskReg_Setting	dc.b %00000101
;****************************************************************
; IRQ Vectors							*
;****************************************************************
	ORG EPROM_IRQVecs
TimerIRQVec	dc.w Timer_IRQ
ExtIRQVec	dc.w Dummy_IRQ
SWIRQVec	dc.w Timer_IRQ
ResetVec	dc.w MC68705_Init