#include "dt_inc.s"
.text
.org 0x0
start:
	br+ main
	br+ main
	ret
main:
	call+ u_init
	call+ u_recv_byte
	call u_send_newline

	ldis r1, 0x41 ; 'A'
	call u_send_byte

	call lcd_init
	ldis r1, 0x42 ; 'B'
	call u_send_byte

	call lcd_clear
	ldis r1, 0x43 ; 'C'
	call u_send_byte

	call lcd_home
	ldis r1, 0x44 ; 'D'
	call u_send_byte

	call delay5ms ; print 'E' on LCD and UART
	ldis r1, 0x45 ; 'E'
	push r1
	call lcd_data
	pop r1
	call+ u_send_byte
	call+ u_send_newline

loop:
	call+ u_recv_byte ; print received Char on LCD
	addi r1, r0, 0
	call+ lcd_data
	br loop

hang: br+ hang

	.define LCD_BASE, 0x2050
	; http://www.mikrocontroller.net/articles/AVR-Tutorial:_LCD#Routinen_zur_LCD-Ansteuerung
lcd_data:
	lrs r2, r1, 4
	andx r2, 0xf
	orx r2, 0x10
	stw r2, 0(r12)
	call+ lcd_enable

	andx r1, 0xf
	orx r1, 0x10
	stw r1, 0(r12)
	call+ lcd_enable

	call+ delay50us
	ret

lcd_command:
	lrs r2, r1, 4
	andx r2, 0xf
	stw r2, 0(r12)
	call+ lcd_enable

	andx r1, 0xf
	stw r1, 0(r12)
	call+ lcd_enable

	call+ delay50us
	ret

lcd_enable:
	addinv r0, r0, 0
	addinv r0, r0, 0
	addinv r0, r0, 0
	ldw r0, 0(r12)
	orx r0, 0x20
	stw r0, 0(r12)
	addinv r0, r0, 0
	addinv r0, r0, 0
	addinv r0, r0, 0
	addinv r0, r0, 0
	addinv r0, r0, 0
	ldw r0, 0(r12)
	ldis r5, 0xffdf
	and r0, r0, r5
	stw r0, 0(r12)
	ret

delay50us: ; @ 50 MHz
	ldis r0, 2500/2
	;ldis r0, 4000/2
delay50us_:
	subi r0, r0, 1
	brnz+ delay50us_ ; not zero
	ret

delay5ms: ; @ 50 MHz
	ldis r0, 5
	;ldis r0, 7
delay5ms_1:
	ldis r1, 50000/2
delay5ms_2:
	subi r1, r1, 1
	brnz+ delay5ms_2 ; not zero
	subi r0, r0, 1
	brnz+ delay5ms_1 ; not zero
	ret

lcd_init:
	ldis r12, LCD_BASE@lo
	ldih r12, LCD_BASE@hi
	ldis r3, 50
powerupwait:
	call+ delay5ms
	subi r3, r3, 1
	brnz+ powerupwait

	ldis r3, 0x3
	stw r3, 0(r12)
	call+ lcd_enable
	call+ delay5ms
	call+ lcd_enable
	call+ delay5ms
	call+ lcd_enable
	call+ delay5ms

	ldis r3, 0x2
	stw r3, 0(r12)
	call+ lcd_enable
	call+ delay5ms

	ldis r1, 0x24
	call+ lcd_command
	ldis r1, 0xc
	call+ lcd_command
	ldis r1, 0x4
	call+ lcd_command
	ret

lcd_clear:
	ldis r1, 0x1
	call lcd_command
	call delay5ms
	ret

lcd_home:
	ldis r1, 0x2
	call lcd_command
	call delay5ms
	ret