;***************************************************************************
; Application:  Led flasher
; Author:       Dan Williams
; Date:         
; Assembler:    AVR Studio 4.07.
; Target:       Atmel ATtiny13.
;***************************************************************************
;------ objective -----
;PB0  PWM1   
;PB1  PWM2   
;PB2  ANA2   
;PB3  SC
;PB4  SD
;PB5  ANA1  
;
;---- this test -----
;PB0  LED1
;PB1  LED2
;PB2  LED3
;PB3  SC
;PB4  SD
;PB5  LED4
;
;****************************************************************************

.device ATtiny13 

; ------------- Memory locations ---------------
;
;  .def bar =r01 ; one byte ram location
;
; ----------------------------------------------

; R 0 ->15 are gen. purp.

.def A          = r16    
.def B          = r17            ; and logic instructions
.def C          = r18
.def D          = r19

.def curstate   = r20
.def laststate  = r21
.def i2cin      = r22
.def bitcount   = r23
.def i2cstat    = r24
.def curbyte    = r25
.def _V         = r26
.def _w         = r27
.def _X         = r28
.def _Y         = r29
.def _Z         = r30


;cant use r25 -> r31

; ------------- Equates ------------------

.equ TRUE    = 1
.equ FALSE   = 0

.equ INPUT   = 0
.equ OUTPUT  = 1

; --- Port Directions ---
.equ PB0DIR  = OUTPUT
.equ PB1DIR  = OUTPUT
.equ PB2DIR  = INPUT
.equ PB3DIR  = INPUT
.equ PB4DIR  = INPUT
.equ PB5DIR  = OUTPUT

; --- Initial port state ---
.equ INPB0   = 0
.equ INPB1   = 0
.equ INPB2   = 0
.equ INPB3   = 0
.equ INPB4   = 0
.equ INPB5   = 0

; --- Port Names ---
.equ LED1    = 0  ; start /  stop
.equ LED2    = 1  ; 1 / 0
.equ LED3    = 2  ; 
.equ SC      = 3  
.equ SD      = 4  
.equ LED4    = 5  ; RESET

; --- amalgimate ---

.equ INITDIR   = ((PB5DIR<<DDB5)|(PB4DIR<<DDB4)|(PB3DIR<<DDB3)|(PB2DIR<<DDB2)|(PB1DIR<<DDB1)|(PB0DIR<<DDB0))
.equ INITSTATE = ((INPB5<<PORTB5)|(INPB4<<PORTB4)|(INPB3<<PORTB3)|(INPB2<<PORTB2)|(INPB1<<PORTB1)|(INPB0<<PORTB0))

; --- flags for i2cstat ---

.equ SELECTED  = 0
.equ DIRECTION = 1
.equ   SEND      = 0
.equ   RECIEVE   = 1
.equ BYTETYPE  = 2
.equ   ADDRESS   = 0
.equ   DATA      = 1
.equ _c1       = 3
.equ _d1       = 4
.equ _e1       = 5
.equ _f1       = 6
.equ _g1       = 7


;========================| SYSTEM VECTORS |===========================
;
.cseg                                   ;CODE segment
.org 0x0000
    rjmp    init   ; RESET 
    reti           ; EXT_INT0  
    reti           ; PCINT0   (pin change)
    reti           ; TIM0_OVF  
    reti           ; EE_RDY  
    reti           ; ANA_COMP  
    reti           ; TIM0_COMPA  
    reti           ; TIM0_COMPB  
    reti           ; WATCHDOG  
    reti  ;rjmp copybit   ; ADC  

;=============================| MAIN |================================
;


.org 0x000A
init:   
        ; Set up stack
        ldi     A,   low(RAMEND)        ; load low address of ram to R16...
        out     SPL, A               ; Set Stack Pointer to top of RAM

        ; Disable interrupts
        cli        

        ; Set up io ports
        ldi   A,    INITSTATE
        out   PORTB, A
        ldi   A,    INITDIR
        out   DDRB,  A

        rcall pwm_init
        rcall adc_init
        
        ;Enable interrupts
        sei   


MainLoup:
     
         ; copy data
     IN  A, ADCH
     OUT OCR0A, A  
     
        rjmp    MainLoup                ; go back and do it all over again


;========================| SUBROUTINES |==============================
;

copybit:
     ; copy data
     IN  A, ADCH
     OUT OCR0A, A  
     cbi ADCSRA, ADIF       
 reti


pwm_init:
  ; clear pwm levels
  ldi  A, 0x3F
  out  OCR0A, A 
  ldi  A, 0xBF
  out  OCR0B, A
  ; set up TCCR0A
  ldi  A, 0xA3
  out  TCCR0A, A
  ; set up TCCROB
  ldi  A, 0x02
  out  TCCR0B, A
 ret

adc_init:
  ; set up adc1 as analog input
  ldi A, 0x08
  out DIDR0, A
  ; auto trigger to free running
  ldi A, 0x00
  out ADCSRB, A
  ; set mux channel
  ldi A, 0x21
  out ADMUX, A
  ; turn system on
  ldi A, 0xEE
  out ADCSRA, A
 ret