#!/usr/bin/env python
# File rpi_lcd.py

# http://www.bristolwatch.com/rpi/rpi_arduino2.htm
# By Lewis Loflin - lewis@bvu.net

# access to GPIO must be through root
import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False) # disable warnings

Line1 = 0x80  # location LCD row 0 col 0 or line 1
Line2 = 0xC0  # location LCD row 1 col 0 or line 2

# Bit_out  Pin 1-2 SN74164
lcdBit = 18
# CLK  Pin 9 SN74164 - clock bit - LOW to HIGH to LOW
lcdClk = 23
# RS Pin 4 LCD  - LOW command; HIGH ASCII
RS = 24
# E Pin 6 LCD - clock data into LCD - HIGH to LOW to HIGH
E = 25

GPIO.setup(lcdBit, GPIO.OUT) 
GPIO.setup(lcdClk, GPIO.OUT) 
GPIO.setup(RS, GPIO.OUT) 
GPIO.setup(E, GPIO.OUT)

# Setup IO
GPIO.output(lcdBit, 0)
GPIO.output(lcdClk, 0)
GPIO.output(RS, 0)
GPIO.output(E, 1)


# GPIO.output(RS, 0)


def pulseCLK():
    GPIO.output(lcdClk, 1)
   # time.sleep(.01) 
    GPIO.output(lcdClk, 0)
    return

def pulseE():
    GPIO.output(E, 0)
   # time.sleep(.01)
    GPIO.output(E, 1)
    return

# MSB out first!
def ssrWrite(value):
    for  x in range(0,8):
        temp = value & 0x80
        if temp == 0x80:
           GPIO.output(lcdBit, 1) # data bit HIGH
        else:
           GPIO.output(lcdBit, 0) # data bit LOW
        pulseCLK()
        value = value << 0x01 # shift left
        time.sleep(.001)
    GPIO.output(lcdClk, 0)
    GPIO.output(lcdBit, 0)
    return 


def initLCD():
    GPIO.output(RS, 0) # RS LOW
    ssrWrite(0x38) # setup for 2 lines
    pulseE()
    ssrWrite(0x0F) # blinking cursor
    pulseE()
    clearLCD()
    Home()
    return 

def clearLCD():
    GPIO.output(RS, 0) # RS LOW
    ssrWrite(0x01) # clear
    pulseE()
    return
    
def Home():
    GPIO.output(RS, 0) # RS LOW
    ssrWrite(0x02) # home
    pulseE()
    return 
    

def gotoLocation(val):
    GPIO.output(RS, 0) # RS LOW
    if val < 0x80:
        val = 0x80
    ssrWrite(val)
    pulseE()
    return


def writeString(myString):
    i = len(myString)
    GPIO.output(RS, 1) # RS - HIGH is ASCII
    for  x in range(0,i):
       y = ord(myString[x])
       ssrWrite(y)
       pulseE()
    GPIO.output(RS, 0) # RS LOW
    return

# convert an 8-bit number to a binary string
def convBinary(value):
    binaryValue = '0b'
    for  x in range(0,8):
        temp = value & 0x80
        if temp == 0x80:
           binaryValue = binaryValue + '1'
        else:
            binaryValue = binaryValue + '0'
        value = value << 1
    return binaryValue


initLCD()

Home()

# these are sample progems.

# display 0-255 in binary on LCD
for j in range(0, 256):
    myStr1 = convBinary(j)
    writeString(myStr1)
    time.sleep(.2)
    Home()


# print j in HEX, OCT, base 10
for j in range(0, 256):
    writeString('J = ' + str(j)) # base 10
    gotoLocation(Line1 + 8)
    writeString('OCT ' + oct(j)) # print octal
    gotoLocation(Line2)
    writeString('HEX ' + hex(j)) # print hex
    time.sleep(.3)
    Home()

GPIO.cleanup()  

exit