; ***************************************************************************
; defines

.equ LCD_CONTROLBYTE_DC_MASK = 0x40
.equ LCD_CONTROLBYTE_CO_MASK = 0x80

.equ LCD_TWI_ADDRESS         = 0x3c

.equ LCD_WIDTH               = 128
.equ LCD_HEIGHT              = 64



; ***************************************************************************
; data

.dseg

lcdDataBegin:
lcdDataEnd:



; ***************************************************************************
; code

.cseg




LCD_Init:
 sbi DDRA, PORTA2 ; debug
 sbi PORTA, PORTA2 ; debug (off)

  ldi zl, LOW(lcdInitCommandsBegin)
  ldi zh, HIGH(lcdInitCommandsBegin)
  ldi r16, (lcdInitCommandsEnd-lcdInitCommandsBegin)*2
  rcall lcdWriteCommandsFromFlash

  ldi r16, 0
  rcall LCD_Fill

  sec
  ret




; - R16: number of bytes to send
; - Z=pointer to data
lcdWriteCommandsFromFlash:
  rcall twiStart
  lsl zl
  rol zh
  mov r20, r16   ; number of bytes
  ldi r16, (LCD_TWI_ADDRESS*2)
  rcall twiSendByte
  brcc lcdWriteCommandsFromFlash_error
  tst r16
  brne lcdWriteCommandsFromFlash_error
  
lcdWriteCommandsFromFlash_loop:
    lpm r16, z+
    rcall twiSendByte
    brcc lcdWriteCommandsFromFlash_error
    tst r16
    brne lcdWriteCommandsFromFlash_error
    dec r20
  brne lcdWriteCommandsFromFlash_loop
  rcall twiStop
 sbi DDRA, PORTA2 ; debug
 cbi PORTA, PORTA2 ; debug (on)
  sec
  ret

lcdWriteCommandsFromFlash_error:
  rcall twiStop
  clc
  ret



; - R16: data to write
LCD_Fill:
  mov r20, r16

  rcall twiStart

  ldi r16, (LCD_TWI_ADDRESS*2)
  rcall twiSendByte
  brcc LCD_Fill_error
  tst r16
  brne LCD_Fill_error

  ldi r21, 0 ; Y
LCD_Fill_loopY:
    ldi r16, 0xb0          ; set page address (data byte and next control byte follow, data byte is a command)
    add r16, r21
    rcall twiSendByte
    brcc LCD_Fill_error
    tst r16
    brne LCD_Fill_error
    ldi r16, 0x01          ; set lower column address
    rcall twiSendByte
    brcc LCD_Fill_error
    tst r16
    brne LCD_Fill_error
  
    ldi r16, 0x10          ; set higher column bits
    rcall twiSendByte
    brcc LCD_Fill_error
    tst r16
    brne LCD_Fill_error
  
    ldi r19, 0
LCD_Fill_loopX:
      mov r16, r20
      rcall twiSendByte
      brcc LCD_Fill_error
      tst r16
      brne LCD_Fill_error
      inc r19
      cpi r19, LCD_WIDTH
    brcs LCD_Fill_loopX
    
    inc r21
    cpi r21, 8
  brcs LCD_Fill_loopY
  rcall twiStop
  sec
  ret
LCD_Fill_error:
  rcall twiStop
  clc
  ret




lcdInitCommandsBegin:  ; 28 bytes
  .db 0xae, 0x00, 0x10, 0x40, 0x81, 0xcf, 0xa1, 0xc8
  .db 0xa6, 0xa8, 0x3f, 0xd3, 0x00, 0xd5, 0x80, 0xd9
  .db 0xf1, 0xda, 0x12, 0xdb, 0x40, 0x20, 0x02, 0x8d
  .db 0x14, 0xa4, 0xa6, 0xaf
lcdInitCommandsEnd: