org	100h

siob_data	equ	083h
siob_ctrl	equ	082h

lcd_data	equ	0dbh
lcd_ctrl	equ	0dah

celcius_offset	equ	08ah
pressure_offset	equ	0cah
humid_offset	equ	09eh

bdos	equ	0005h
conout  equ	02h
conin	equ	01h

char_idx	equ	10h

temperature	equ	20h
humidity	equ	30h
pressure	equ	40h

start:
	call	init_lcd
	call	init_siob
	call	lcd_delay

	ld	a,celcius_offset ; write celcius label
	out	(lcd_ctrl),a
	call	lcd_delay
	ld	hl,clabel
	call	print_str_to_lcd

	ld	a,pressure_offset ; write pressure label
	out	(lcd_ctrl),a
	call	lcd_delay
	ld	hl,plabel
	call	print_str_to_lcd

	ld	a,humid_offset ; write humidity label
	out	(lcd_ctrl),a
	call	lcd_delay
	ld	hl,hlabel
	call	print_str_to_lcd

main:
	call	read_char_b
	call	parse_char
	;call	print_char_to_lcd
	ld	c,11
	call	bdos
	or	a
	jr	z,main
	ret

init_siob:
	ld	a,018h		; channel reset
	out	(siob_ctrl),a

	ld	a,04h
	out	(siob_ctrl),a	; wr4 baud settings
	ld	a,0c4h
	out	(siob_ctrl),a

	ld	a,03h
	out	(siob_ctrl),a	; rx enable
	ld	a,0c1h
	out	(siob_ctrl),a

	ld	a,05h
	out	(siob_ctrl),a	; tx settings
	ld	a,0eah
	out	(siob_ctrl),a

	ret

init_lcd:
	ld	a,38h
	out	(lcd_ctrl),a	; function 8 bit, 2 lines, 5x8 dot font
	call	lcd_delay
	ld	a,0ch
	out	(lcd_ctrl),a	; display on, cursor off, no blink
	call	lcd_delay
	ld	a,01h
	out	(lcd_ctrl),a	; clear display

	ret

lcd_delay:
	ld	bc,500
delay1:
	dec	bc
	ld	a,b
	or	c
	jr	nz,delay1
	ret

convert_to_hpa:
	ld	a,(pressure)

read_char_b:
wait:
	in	a,(siob_ctrl)
	bit	0,a
	jr	z,wait

	in	a,(siob_data)
	ret

parse_char:	; char should be in register a
	cp	a,25h	; percent sign (end of transmission)
	jr	z,print_telem_to_lcd
	cp	a,0dh	; carriage return
	jr	z,null_term
	cp	a,0ah	; new line
	jr	z,parse_char_done
	cp	a,054h	; T character
	jr	z,set_char_idx_t	; point the char_idx to the temperature buffer
	cp	a,050h	; P character
	jr	z,set_char_idx_p	; point the char_idx to the pressure buffer
	cp	a,048h	; H character
	jr	z,set_char_idx_h	; point the char_idx to the humidity buffer
	
	ld	bc,(char_idx)	; get address stored in char_idx
	ld	(bc),a		; deref that address and store char
	inc	bc
	ld	(char_idx),bc	; store incremented address in char_idx

	;out	(lcd_data),a
parse_char_done:
	ret

print_telem_to_lcd:
	call	move_to_tempaddr
	ld	hl,temperature
	call	print_str_to_lcd
	ld	a,1h
	out	(0),a
	ret

null_term:	; null terminate end of parsed string in memory
	ld	a,00h
	ld	bc,(char_idx)
	ld	(bc),a
	jr	parse_char_done


set_char_idx_t:
	ld	bc,temperature
	ld	(char_idx),bc
	ret

set_char_idx_p:
	ld	bc,pressure
	ld	(char_idx),bc
	ret

set_char_idx_h:
	ld	bc,humidity
	ld	(char_idx),bc
	ret


print_char_to_lcd:
	cp	a,00h	; null byte
	jr	z,lcd_done
	cp	a,0dh	; carriage return
	jr	z,lcd_done
	cp	a,0ah	; new line
	jr	z,lcd_done
	cp	a,054h	; T character
	call	z,move_to_tempaddr
	cp	a,050h	; P character
	call	z,move_to_presaddr
	cp	a,048h	; H character
	call	z,move_to_humidaddr
	out	(lcd_data),a
lcd_done:
	ret	

print_str_to_lcd:	; place memory address in hl first
	ld	a,(hl)
	or	a
	jr	z,print_done

	out	(lcd_data),a
	call	lcd_delay
	inc	hl
	jr	print_str_to_lcd
print_done:
	ret

move_to_tempaddr:
	ld	c,a
	ld	a,85h
	out	(lcd_ctrl),a
	ld	a,c
	ret

move_to_presaddr:
	ld	a,0c1h
	out	(lcd_ctrl),a
	ret

move_to_humidaddr:
	ld	a,99h
	out	(lcd_ctrl),a
	ret

clabel: DB 'degree C',0
plabel: DB 'pascal',0
hlabel: DB '% RH',0

	end	start