;LCD code for AT90S2313
;use with 16x2  LCD display
;2313-lcd.asm

.device AT90S2313

;***** I/O Register Definitions
.equ SREG =$3f
.equ SPH  =$3e
.equ SPL  =$3d
.equ GIMSK =$3b
.equ GIFR =$3a
.equ TIMSK =$39
.equ TIFR =$38
.equ MCUCR =$35
.equ TCCR0 =$33
.equ TCNT0 =$32
.equ TCCR1A =$2f
.equ TCCR1B =$2e
.equ TCNT1H =$2d
.equ TCNT1L =$2c
.equ OCR1AH =$2b
.equ OCR1AL =$2a
.equ ICR1H =$25
.equ ICR1L =$24
.equ WDTCR =$21
.equ EEAR =$1e
.equ EEARL =$1e
.equ EEDR =$1d
.equ EECR =$1c
.equ PORTB =$18
.equ DDRB =$17
.equ PINB =$16
.equ PORTD =$12
.equ DDRD =$11
.equ PIND =$10
.equ UDR =$0c
.equ USR =$0b
.equ UCR =$0a
.equ UBRR =$09
.equ ACSR =$08


;***** Bit Definitions
.equ SP7 =7
.equ SP6 =6
.equ SP5 =5
.equ SP4 =4
.equ SP3 =3
.equ SP2 =2
.equ SP1 =1
.equ SP0 =0

.equ INT1 =7
.equ INT0 =6

.equ INTF1 =7
.equ INTF0 =6

.equ TOIE1 =7
.equ OCIE1A =6
.equ TICIE =3
.equ TOIE0 =1

.equ TOV1 =7
.equ OCF1A =6
.equ ICF1 =3
.equ TOV0 =1

.equ SE =5
.equ SM =4
.equ ISC11 =3
.equ ISC10 =2
.equ ISC01 =1
.equ ISC00 =0

.equ CS02 =2
.equ CS01 =1
.equ CS00 =0

.equ COM1A1 =7
.equ COM1A0 =6
.equ PWM11 =1
.equ PWM10 =0

.equ ICNC1 =7
.equ ICES1 =6
.equ CTC1 =3
.equ CS12 =2
.equ CS11 =1
.equ CS10 =0

.equ WDTOE =4
.equ WDE =3
.equ WDP2 =2
.equ WDP1 =1
.equ WDP0 =0

.equ EEMWE =2
.equ EEWE =1
.equ EERE =0

.equ PB7 =7
.equ PB6 =6
.equ PB5 =5
.equ PB4 =4
.equ PB3 =3
.equ PB2 =2
.equ PB1 =1
.equ PB0 =0

.equ DDB7 =7
.equ DDB6 =6
.equ DDB5 =5
.equ DDB4 =4
.equ DDB3 =3
.equ DDB2 =2
.equ DDB1 =1
.equ DDB0 =0

.equ PINB7 =7
.equ PINB6 =6
.equ PINB5 =5
.equ PINB4 =4
.equ PINB3 =3
.equ PINB2 =2
.equ PINB1 =1
.equ PINB0 =0

.equ PD6 =6
.equ PD5 =5
.equ PD4 =4
.equ PD3 =3
.equ PD2 =2
.equ PD1 =1
.equ PD0 =0

.equ DDD6 =6
.equ DDD5 =5
.equ DDD4 =4
.equ DDD3 =3
.equ DDD2 =2
.equ DDD1 =1
.equ DDD0 =0

.equ PIND6 =6
.equ PIND5 =5
.equ PIND4 =4
.equ PIND3 =3
.equ PIND2 =2
.equ PIND1 =1
.equ PIND0 =0

.equ RXC =7
.equ TXC =6
.equ UDRE =5
.equ FE =4
.equ OR =3

.equ RXCIE =7
.equ TXCIE =6
.equ UDRIE =5
.equ RXEN =4
.equ TXEN =3
.equ CHR9 =2
.equ RXB8 =1
.equ TXB8 =0

.equ ACD =7
.equ ACO =5
.equ ACI =4
.equ ACIE =3
.equ ACIC =2
.equ ACIS1 =1
.equ ACIS0 =0

.equ    RAMEND  =$DF    ;Last On-Chip SRAM Location
.equ XRAMEND =$DF
.equ E2END =$7F
.equ FLASHEND=$3FF

.equ LCDSTART=$C0
.equ LCDEND =LCDSTART+8

.equ INT0addr=$001 ;External Interrupt0 Vector Address
.equ INT1addr=$002 ;External Interrupt1 Vector Address
.equ ICP1addr=$003 ;Input Capture1 Interrupt Vector Address
.equ OC1addr =$004 ;Output Compare1 Interrupt Vector Address
.equ OVF1addr=$005 ;Overflow1 Interrupt Vector Address
.equ OVF0addr=$006 ;Overflow0 Interrupt Vector Address
.equ URXCaddr=$007 ;UART Receive Complete Interrupt Vector Address
.equ UDREaddr=$008 ;UART Data Register Empty Interrupt Vector Address
.equ UTXCaddr=$009 ;UART Transmit Complete Interrupt Vector Address
.equ ACIaddr =$00a ;Analog Comparator Interrupt Vector Address


;Define register name
; r0 is used by Z-registor

.def temp1 =r16
.def temp2 =r17
.def temp3 =r18
.def temp4 =r19
.def temp5 =r20
.def temp6 =r21
.def LCDPOINTER=r22
.def delay =r24
.def  W  =r25
.def XL  =r26
.def XH  =r27
.def YL  =r28
.def YH  =r29
.def ZL  =r30
.def ZH  =r31

.equ PORTLCD =PORTB
.equ DDRLCD =DDRB
.equ PINLCD =PINB

.cseg ;This tells the assembler that what follows is code, and goes in ROMspace
.org $000
 rjmp RESET  
 rjmp EXT_INT0 ; IRQ0
 rjmp EXT_INT1 ; IRQ1
 rjmp TIM1_CAPT ; Timer1 Capture
 rjmp TIM1_COMP ; Timer1 Compare
 rjmp TIM1_OVF ; Timer1 Overflow
 rjmp TIM0_OVF ; Timer0 Overflow
 rjmp UART_RXC ; UART Receive
 rjmp UART_DRE ; UART empty
 rjmp UART_TXC ; UART Transmit
 rjmp ANA_COMP ; Analog comparator

RESET: ;init everything here
 ldi temp1,low(RAMEND)
 out SPL,temp1  ; Set stack pointer to last internal RAM location
 ldi temp1,high(RAMEND)
 out SPH,temp1

 ldi temp1,5  ;set timer0 prescale divisor to 1024
 out TCCR0,temp1 ;using 10.24 XTAL you get 10,000 Hz/100uS
 ldi temp1,$02
 out TIMSK,temp1 ;enable TIMER0 overflow interrupts

EI: sei ;global all interrupt enable

 rcall initlcd
 rcall lcdclear

 ldi ZH,high(2*msg1)
 ldi ZL,low(2*msg1)
 rcall loadbytes

 ;rcall lcdhome

menu: ;main program
 ldi temp1,$C5
 rcall lcdcmd
 ldi temp1,$37
 rcall lcdput
 ldi temp1,$C6
 rcall lcdcmd
 ldi temp1,$33
 rcall lcdput

 ldi temp1,$89
 rcall lcdcmd
 ldi temp1,'o'
 rcall lcdput
 ldi temp1,$8A
 rcall lcdcmd
 ldi temp1,'o'
 rcall lcdput

lockup:
 rjmp lockup

initlcd:
 ldi temp1,0
 out PORTLCD,temp1 ;turn off any pullup resistors
 ldi temp1,$7F
 out DDRLCD, temp1 ;set LCD port for output
 ldi delay,4   ;wait at least 15ms after Vcc=4.5V
 rcall WaitForDelay
 ldi temp1,3  ;function set
 out PORTLCD,temp1
 rcall toggleE
 ldi delay,2  ;wait 10 ms
 rcall WaitForDelay
 ldi temp1,3  ;function set
 out PORTLCD,temp1
 rcall toggleE
 ldi delay,2  ;wait 10 ms
 rcall WaitForDelay
 ldi temp1,3  ;function set
 out PORTLCD,temp1
 rcall toggleE
 ldi temp1,2  ;function set, 4 line interface
 out PORTLCD,temp1
 rcall toggleE
 ldi temp1,$70 ;make 4 data lines inputs
 out DDRLCD,temp1
 ldi temp1,$28 ;function set 4-wire, 2-line, 5x7
 rcall lcdcmd
 ldi temp1,$0C ;display on, cursor off, blink off
 rcall lcdcmd
 ldi temp1,$06 ;address inc, no scroll
 rcall lcdcmd
 ret

lcdwait:    ;wait for lcd not busy
 push temp1
 push temp2
 ldi temp1,$F0  ;make 4 data lines input
 out PORTLCD,temp1
 sbi PORTLCD,PB5  ;set r/w to read
 cbi PORTLCD,PB6  ;set register select to command
 nop     ;wait for data setup time
 nop     ;delay 140 ns
waitloop:
 sbi PORTLCD,PB4  ;set E high
 nop     ;delay 450 ns
 nop
 nop
 nop
 nop
 cbi PORTLCD,PB4  ;set E low
 in  temp2,PINLCD ;read busy flag
 rcall toggleE
 sbrc temp2,3 ;loop until done 
 rjmp waitloop
 pop temp2
 pop temp1
 ret

lcdcmd: ;send cmd in temp1
 rcall lcdcmd2
lcdcmd2:
 mov temp2,temp1
 rcall lcdwait
 ldi temp1,$7F
 out DDRLCD,temp1 ;set LCD port for output
 mov temp1,temp2
 swap temp1
 andi temp1,$0F
 out PORTLCD,temp1
 rcall toggleE
 mov temp1,temp2
 andi temp1,$0F  ;strip off upper bits
 out PORTLCD,temp1
 rcall toggleE
 ldi temp1,$70  ;make 4 data lines input
 out DDRLCD,temp1
 mov temp1,temp2
 ret

lcdput:
 push temp1
 push temp2
 mov temp2,temp1
 rcall lcdwait
 ldi temp1,$7F
 out DDRLCD,temp1 ;set LCD port for output
 mov temp1,temp2
 mov temp2,temp1
 swap temp1
 andi temp1,$0F  ;send upper nibble data
 out PORTLCD,temp1 ;send data to LCD
 sbi PORTLCD,PB6  ;set register select to data
 rcall toggleE
 mov temp1,temp2
 andi temp1,$0F  ;send lower nibble data
 out PORTLCD,temp1 ;send data to LCD
 sbi PORTLCD,PB6  ;set register select to data
 rcall toggleE
 ldi temp1,$70  ;make 4 data lines input
 out DDRLCD,temp1
 pop temp2
 pop temp1
 ret

toggleE:
 nop     ;wait for data setup time
 nop     ;delay 140 ns
 sbi PORTLCD,PB4  ;set E high
 nop     ;delay 450 ns
 nop
 nop
 nop
 nop
 cbi PORTLCD,PB4  ;set E low
 ret

lcdclear:
 ;ldi temp1,3
 ;rcall lcdcmd
 ldi temp1,1
 rcall lcdcmd
 ret

lcdhome:
 ;ldi temp1,3
 ;rcall lcdcmd
 ldi temp1,2
 rcall lcdcmd
 ret

loadbytes:
 lpm
 tst r0
 breq bytesloaded
 mov temp1,r0
 rcall lcdput
 adiw ZL,1
 rjmp loadbytes
bytesloaded:
 ret

WaitForDelay:
 tst delay
 brne WaitForDelay
 ret

EXT_INT0:
 push temp1
 in  temp1,SREG ;save the status register

 out  SREG,temp1 ;restore the status register
 pop  temp1
 reti

EXT_INT1:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti 

TIM1_CAPT:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

TIM1_COMP:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

TIM1_OVF:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

TIM0_OVF:
 push temp1
 in temp1,SREG
 push temp1

;this is for a 8,192 KHz Xtal
 ;ldi temp,$F8 ;1 ms
 ;ldi temp,$F0 ;2 ms
 ;ldi temp,$E0 ;4 ms
 ;ldi temp1,$D8 ;5 ms
 ;ldi temp,95 ;20 ms

;this is for a 10,240 KHz Xtal
 ;ldi temp,$F6 ;1 ms
 ;ldi temp,$EC ;2 ms
 ;ldi temp,$D8 ;4 ms
 ldi temp1,$CE ;5 ms
 ;ldi temp,56 ;20 ms

 out TCNT0,temp1 ;set for next overflow
 tst delay
 breq TIM0_EXIT
 dec delay

TIM0_EXIT:
 pop temp1
 out SREG,temp1
 pop  temp1
 reti

UART_RXC:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

UART_DRE:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

UART_TXC:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

ANA_COMP:
 push temp1
 in temp1,SREG

 out SREG,temp1
 pop  temp1
 reti

msg1:
;    1234567890123456789012345678901234567890
.db "LCD Test",0