lcd16x2.lua

#!/usr/bin/luajit

local wpi = require ("wiringlua")

local ADDR = 0x27
local BLEN = 1
local fd = 0

function write_word(data)
	local temp = data
	if BLEN == 1 then
		temp = bit.bor(temp, 0x08)
	else
		temp = bit.band(temp, 0xF7)
	end
	wpi.i2c.write(fd, temp)
end

function send_command(comm)
	local buf
	buf = bit.band(comm, 0xF0)
	buf = bit.bor(buf, 0x04)
	write_word(buf)
	wpi.timer.delay(2)
	buf = bit.band(buf, 0xFB)
	write_word(buf)

	buf = bit.lshift(bit.band(comm, 0x0F), 4)
	buf = bit.bor(buf, 0x04)
	write_word(buf)
	wpi.timer.delay(2)
	buf = bit.band(buf, 0xFB)
	write_word(buf)
end

function send_data(data)
	local buf
	buf = bit.band(data, 0xF0)
	buf = bit.bor(buf, 0x05)
	write_word(buf)
	wpi.timer.delay(2)
	buf = bit.band(buf, 0xFB)
	write_word(buf)

	buf = bit.lshift(bit.band(data, 0x0F), 4)
	buf = bit.bor(buf, 0x05)
	write_word(buf)
	wpi.timer.delay(2)
	buf = bit.band(buf, 0xFB)
	write_word(buf)
end

function init()
	send_command(0x33)
	wpi.timer.delay(5)
	send_command(0x32)
	wpi.timer.delay(5)
	send_command(0x28)
	wpi.timer.delay(5)
	send_command(0x0C)
	wpi.timer.delay(5)
	send_command(0x01)
	wpi.i2c.write(fd, 0x08)
end

function clear()
	send_command(0x01)
end

function write(x, y, string)
	local addr, tmp
	if x < 0 then x = 0 end
	if x > 15 then x = 15 end
	if y < 0 then y = 0 end
	if y > 1 then y = 1 end

	addr = 0x80 + 0x40 * y + x
	send_command(addr)

	tmp = #string
	for i=1,#string do
		send_data(string.byte(string:sub(i,i)))
	end
end


fd = wpi.i2c.setup(ADDR)
init()
write(0, 0, "HELLO FROM")
write(9, 1, "LUAJIT!")
print("FD = " .. fd)