;
; hello.echo.44.asm
;
; 115200 baud serial echo and LED hello-world program
;
; Neil Gershenfeld
; CBA MIT 7/28/07
;
; (c) Massachusetts Institute of Technology 2007
; Permission granted for experimental and personal use;
; license for commercial sale available from MIT.
;

;
;cp (compare)
;brne (branch if not equal)
;breq (branch if equal)
;sbic (skip if bit in I/O register cleared)
;sbis (skip if bit in I/O register set)
;
;
;

.include "tn44def.inc"


.equ ledpa0 = PA0 ; LED source pin
.equ ledpa1 = PA1 ; LED source pin
.equ ledpa2 = PA2 ; LED source pin
.equ ledpa3 = PA3 ; LED source pin

.equ button = PB2 ; LED source pin

.equ txpin = PA6; transmit pin
.equ rxpin = PA7; receive pin

.def bitcnt = R16; bit counter
.def temp = R17; temporary storage
.def temp1 = R18; temporary storage
.def temp2 = R21
.def temp3 = R22
.def temp4 = R23

.def temp6 = R24
.def temp7 = R25
.def temp8 = R26

.def temp9 = R27
.def temp10 = R28

.def count_reg = R29
.def count_reg2 = R30

.def txbyte = R19; transmit byte
.def rxbyte = R20; receive byte

;
; print
; 
.macro print
   ldi zl,low(@0*2)
   ldi zh,high(@0*2)
   rcall print_db
   .endmacro
;
; putbitdelay
; putchar bit delay
; 115200 baud, 20 MHz clock /8
;
.macro putbitdelay
   nop ;(NO OPERATION - PERFORMS A SINGLE CYCLE WITH NO OPERATION)
   nop
   nop
   nop
   nop
   nop
   nop
   nop
   nop
   nop
   nop
   nop
   .endmacro
;
; getbitdelay
; getchar bit delay
; 115200 baud, 20 MHz clock /8
;
.macro getbitdelay
   nop
   nop
   nop
   nop
   nop
   nop
   nop
   .endmacro

.cseg
.org 0
rjmp reset

;
; putchar
; assumes no line driver (doesn't invert bits)
;

.equ sb = 1; number of stop bits
putchar:
   ldi bitcnt, 9+sb; 1+8+sb (LOAD IMMEDIATE)
   com txbyte; invert everything (ONE'S COMPLEMENT-INVERT EVERYTHING)
   sec; set start bit (SET CARRY)
   putchar0:
      brcc putchar1; if carry set ;(BRANCH IF CARRY CLEARED)
      sbi PORTA, txpin; send a '0' ; (SET BIT IN I/O REGISTER)
      rjmp putchar2; else ; (RELATIVE JUMP)
   putchar1:
       cbi PORTA, txpin	; send a '1' (CLEAR BIT IN I/O REGISTER)
       nop ; even out timing (NO OPERATION ONE CYCLE)
   putchar2:
       putbitdelay; one bit delay (MACRO "putbitdelay")
       lsr txbyte; get next bit (LOGICAL SHIFT RIGHT)
       dec bitcnt; if not all bits sent (DECREMENT)
       brne putchar0; send next bit (BRANCH IF NOT EQUAL)
   ret; (SUBROUTINE RETURN)




;
; getchar
; assumes no line driver (doesn't invert bits)
;
getchar:
   ldi bitcnt,9 ; 8 data bit + 1 stop bit (LOAD IMMEDIATE)
   getchar1:
      ;rcall fdloop_2 ; fade on
      ;rcall fdloop_3 ; fade off
      sbis PINA, rxpin ; wait for start bit (SKIP IF BIT IN I/O REGISTER SET)
      rjmp getchar1 ;(RELATIVE JUMP)
   getbitdelay ; delay to middle of bit MACRO
   getchar2:
      getbitdelay ; delay to next bit
      getbitdelay ; 
      clc ; clear carry
      sbis PINA, rxpin ; if RX pin high skip (SKIP IF BIT IN I/O REGISTER SET)
         sec ; otherwise set carry (SET CARRY)
      dec bitcnt ;(DECREMENT (SUBTRACTS -1- FROM THE CONTENTS OF THE REGISTER)
      breq getchar3 ; return if all bits read (BRANCH IF EQUAL)
      ror rxbyte ; otherwise shift bit into receive byte (ROTATE RIGHT THROUGH CARRY)
      rjmp getchar2 ; go get next bit (RELATIVE JUMP)
   getchar3:
      ret

;
;added script to compare user input to 3
;
getcompare:
     print question
        question: .db "How many times did I blink?",10
     nop
     nop
     nop
     nop




     ldi bitcnt,9
     getcompare1:
        sbis PINA, rxpin
        rjmp getcompare1
        getbitdelay
     getcompare2:
     getbitdelay
     getbitdelay
     clc
     sbis PINA, rxpin
        sec
     dec bitcnt
     breq getcompare3
     ror rxbyte
     rjmp getcompare2


   

getcompare3:
                 print message
      message: .db "you typed: ",0
      mov txbyte, rxbyte ; (COPY REGISTER)
      rcall putchar ; (RELATIVE CALL SUB ROUTINE)
      ldi txbyte,10 ; (LOAD IMMEDIATE)
      rcall putchar ; (RELATIVE CALL SUB ROUTINE)  
     nop
     
     subi rxbyte,48

     ;ldi temp,3

     cp rxbyte, count_reg

     breq getcompare4


      print wrong
           wrong: .db "wrong...",10
     cpi rxbyte,84

     brne getcompare5
     getcompare4:
      

        print right
          right: .db "right!",10
    

     nop
     rcall fdloop_2 ; working fade
     rcall fdloop_3
     rcall fdloop_2 ; working fade
     rcall fdloop_3
     rcall fdloop_2 ; working fade
     
   getcompare5:
     ret






;
; blink
; blink the LED
;
blink:
   sbi PORTA, ledpa0 ;(SET BIT I/O)
   ldi temp, 255 ;(LOAD IMMEDIATE)
   blink_loop:
      ldi temp1, 255 ;(LOAD IMMEDIATE)
      blink_loop1:
         dec temp1 ;(DECREMENT TEMP1)
  	 brne blink_loop1 ;(BRANCH IF NOT EQUAL)
      dec temp ; (DECREMENT TEMP)
      brne blink_loop ; (BRANCH IF NOT EQUAL)
   cbi PORTA, ledpa0
   ret

blink_off:
   sbi PORTA, ledpa0
   cbi PORTA, ledpa0
   ldi temp, 255 
      blink_off_loop:
         ldi temp1, 255
         blink_off_loop1:
           dec temp1
           brne blink_off_loop1
      dec temp
      brne blink_off_loop
   sbi PORTA, ledpa0
   cbi PORTA, ledpa0
   ret   

   
;
; print_db
; prints a null-terminated .db string
;
print_db:
   print_loop:
      lpm ; (LOAD PROGRAM MEMORY)
      mov txbyte,R0 ; (COPY REGISTER)
      cpi txbyte,0 ; (COMPARE WITH IMMEDIATE)
      breq return ; (BRANCH IF EQUAL TO return:)
      rcall putchar ; (relative call)
      adiw zl, 1 ; (ADD IMEDIATE TO WORD in this case 1)
      rjmp print_loop ; relative jump
   return:
      ret
;
; main program
;
reset:
   ;
   ; set fuse low byte to 0x7E for 20 MHz resonator
   ;
   ; set stack pointer to top of RAM
   ;
   ldi temp, high(RAMEND) ;(LOAD IMMEDIATE)
   out SPH, temp; (OUT TO I/O LOCATION)
   ldi temp, low(RAMEND)
   out SPL, temp; (OUT TO I/O LOCATION)
   ;
   ; init comm pin
   ;
   cbi PORTA, txpin ;(CHANGED TO FROM sbi TO cbi clear bit in transmit pin)
   sbi DDRA, txpin ; (SET BIT IN I/O transmit PIN)
   ;
   ; init LED pins
   ;
   cbi PORTA, ledpa0
   sbi DDRA, ledpa0
   
   cbi PORTA, ledpa1
   sbi DDRA, ledpa1

   cbi PORTA, ledpa2
   sbi DDRA, ledpa2

   cbi PORTA, ledpa3
   sbi DDRA, ledpa3

  
   cbi DDRB, button
   sbi PORTB, button

   ;cbi PORTA, led_sink_pin
   ;sbi DDRA, led_sink_pin



   ;
   ; start main loop
   ;
   loop:

     
     nop
     nop
     nop
     nop
     print message3
	 message3: .db "press the button on the board to begin.",10
     nop
     nop
     nop
     nop  
     rcall count_loop
      
      got_random:

      rcall random_blink


      rcall getcompare
      ;rcall getchar ; (RELATIVE CALL SUB ROUTINE)
      ;print message
         ;message: .db "you typed: ",0
      ;mov txbyte, rxbyte ; (COPY REGISTER)
      ;rcall putchar ; (RELATIVE CALL SUB ROUTINE)
      ;ldi txbyte,10 ; (LOAD IMMEDIATE)
      ;rcall putchar ; (RELATIVE CALL SUB ROUTINE)

      

     

     ;rcall led_on ;
     ;rcall delay2 ; on between fd loop and fdloop off
     ;rcall fdloop_off
     
     ;rcall fdloop_2 ; working fade
     ;rcall fdloop_3 ; working fade



     ;rcall led_on ;
     ;rcall led_off
     ;rcall fdloop
     ;rcall delay2
     ;rcall delay ;on between 3 and 2
     
     
     ;rcall fdloop
     ;rcall led_on
     ;rcall delay2
     
     
     
     rjmp loop ; (RELATIVE JUMP)


random_blink:
      ldi count_reg2,0 
      mov count_reg2,count_reg
      random_blink2:
      rcall blink
      rcall blink_off
      dec count_reg2
      cpi count_reg2,0
      brne random_blink2
ret

count_loop:
        ldi count_reg,10
        count_loop2:
           dec count_reg
           rcall button_loop
           count_loop3:
           cpi count_reg,1
           brne count_loop2
        cpi count_reg,1
        breq count_loop
ret


button_loop:

        sbic PINB, button
        rjmp count_loop3

        rjmp got_random
        


ret







led_count:
       led_count2:
       rcall blink
       rcall blink_off
       dec count_reg
       brne led_count2
ret





fdloop_3:




          ldi temp3, 55
        crap4:
        rcall led_off
        rcall delay
        rcall led_on
        rcall fade_on
        dec temp3
        cpi temp3, 1 
        brne crap4
        rcall led_off


ret







fdloop_2:




        ldi temp3, 1
        crap3:
        rcall led_off
        rcall delay
        rcall led_on
        rcall fade_on
        inc temp3
        cpi temp3, 120
        brne crap3
        rcall led_off


ret






fade_on:
 ldi temp, 67
   delay_fade1:
      ldi temp1, 1
      delay_fade2:
         mov temp2, temp3
         delay_fade3:
            dec temp2
            brne delay_fade3
      dec temp1
      brne delay_fade2
   dec temp
   brne delay_fade1
ret


led_on:
      sbi PORTA, ledpa0
      sbi PORTA, ledpa1
      sbi PORTA, ledpa2
      sbi PORTA, ledpa3
   ret




led_off:
      cbi PORTA, ledpa0
      cbi PORTA, ledpa1
      cbi PORTA, ledpa2
      cbi PORTA, ledpa3

   ret





delay2:
   ldi temp6, 255
   delay_loop3:
      ldi temp7, 30
      delay_loop4:
         ldi temp8, 255
         delay_loop5:
            dec temp8
            brne delay_loop5
      dec temp7
      brne delay_loop4
   dec temp6
   brne delay_loop3
   ret




delay:
   ldi temp9, 255
   delay_loop1:
      ldi temp10, 25
      delay_loop2:
      dec temp10
      brne delay_loop2
   dec temp9
   brne delay_loop1
   ret