vfd.py

import serial
import time
import fileinput

port = serial.Serial('/dev/ttyUSB0',19200,serial.EIGHTBITS,serial.PARITY_NONE, 
serial.STOPBITS_ONE,timeout=5,rtscts = False)

def wr(m):
    port.write(m)

NULL = '\x00'
CLEAR = ''.join([chr(254), chr(88)])
WRAPON = ''.join([chr(254), chr(67)])
WRAPOFF = ''.join([chr(254), chr(68)])
SCROLLON = ''.join([chr(254), chr(81)])
SCROLLOFF = ''.join([chr(254), chr(82)])

CURBLINK = ''.join([chr(254), chr(83)])
CURNOBLINK = ''.join([chr(254), chr(84)])
CURHOME = ''.join([chr(254), chr(72)])
CURPOS = ''.join([chr(254), chr(71)]) # then col, row
def curpos(row, col = 0):
    # [0-19] -> 1-20
    port.write(CURPOS)
    port.write(chr(col+1))
    port.write(chr(row+1))
CURMOVELEFT = ''.join([chr(254), chr(76)])
CURMOVERIGHT = ''.join([chr(254), chr(77)])
BRIGHTNESS = ''.join([chr(254), chr(89)])
def brightness(val = 0):
    # [0 to 3] larger = darker
    # 0 = 100%
    # 3 = 25%
    port.write(BRIGHTNESS)
    port.write(chr(val))
DISPLAYON = ''.join([chr(254), chr(66), chr(0)])
DISPLAYOFF = ''.join([chr(254), chr(70)])

wr(CURHOME)
wr(WRAPOFF)
wr(SCROLLOFF)
brightness(3)

row = 0
for line in fileinput.input():
    curpos(row)
    l = (line.strip()).ljust(20)[:20]
    wr(l)
    print("'%s'" % l)
    row = (row + 1) % 4

curpos(3, 19)
"""
curpos(1,0)
wr("one")
curpos(2,0)
wr("two")
curpos(3,0)
wr("three")
curpos(4,0)
wr("four")
"""