LCD1602.py

#!/usr/bin/python3

# This is a more complicated example utilizing a 74HC595 shift register
# to control a 7 segment display. The wiring from the NodeMCU to the
# shift register is described below.

from nodemcu import NodeMcu, NodeMcuError, D
from time import sleep
from sys import exit
from common import getIPPort
from time import sleep

# Wiring       Names from the TI data sheet
DS = D[0]    # SER
ST_CP = D[1] # RCLK
SH_CP = D[2] # SRCLK

E = D[5]
RW = D[6]
RS = D[7]

def init_lcd(mcu):
        sleep(0.01)
        lcdCommand(mcu, 0x38)

        sleep(0.01)
        lcdCommand(mcu, 0x38)

        sleep(0.01)
        lcdCommand(mcu, 0x38)

        sleep(0.01)
        lcdCommand(mcu, 0x06)

        sleep(0.01)
        lcdCommand(mcu, 0x0c)

        sleep(0.01)
        lcdCommand(mcu, 0x01)

def lcdCommand(mcu, cmd):
        mcu.write(RS, False)
        mcu.write(RW, False)
        mcu.write(E, True)

        lcdDataWrite(mcu, cmd)
        sleep(0.01)
        mcu.write(E, False)

def lcdData(mcu, data):
        mcu.write(RS, True)
        mcu.write(RW, False)
        mcu.write(E, True)

        lcdDataWrite(mcu, data)
        sleep(0.01)
        mcu.write(E, False)

def lcdDataWrite(mcu, data):
        move = 0x80

        print("write ", data)
        for i in range(0,8):
                mcu.write(DS, data & move != 0)
                mcu.write(SH_CP, False)
                mcu.write(SH_CP, True)
                move >>= 1

        mcu.write(ST_CP, True)
        mcu.write(ST_CP, False)
        mcu.write(SH_CP, False)


def lcdXY(mcu, x, y):
        x += 0x80
        if y == 1:
                x += 0x40
        lcdCommand(mcu, x)

def lcdString(mcu, s, x=-1, y=-1):
        if x >= 0 and y >= 0:
                lcdXY(mcu, x, y)
        for c in s:
                lcdData(mcu, ord(c))
                sleep(0.05)

def lcdChar(mcu, x, y, ch):
        lcdXY(mcu, x, y)
        lcdData(mcu, ord(ch))


try:
        mcu = NodeMcu(getIPPort())

        for o in [DS, ST_CP, SH_CP, E, RW, RS]:
                mcu.setOutput(o)

        mcu.write(SH_CP, False)
        mcu.write(ST_CP, False)

        init_lcd(mcu)

        while True:
                lcdCommand(mcu, 0x01) # clear screen
                lcdString(mcu, "Hello ESP!", 0, 0)
                sleep(10)


except NodeMcuError as e:
        print("error:", e)