c0deaddict

local bor, band, bnot = bit.bor, bit.band, bit.bnot

local function write4bits(self, bits, char_mode)
  tmr.delay(1000)
  gpio.write(self.pin_rs, char_mode and gpio.HIGH or gpio.LOW)

  for n = 1, 2 do
    for i, pin in ipairs(self.pin_db) do
      local j = (2-n)*4 + (i-1)
      local val = (bit.isset(bits, j))