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Diffstat (limited to 'I2C_LCD_driver.py')
| -rw-r--r-- | I2C_LCD_driver.py | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/I2C_LCD_driver.py b/I2C_LCD_driver.py new file mode 100644 index 0000000..0a58e30 --- /dev/null +++ b/I2C_LCD_driver.py @@ -0,0 +1,178 @@ +# -*- coding: utf-8 -*- +# Original code found at: +# https://gist.github.com/DenisFromHR/cc863375a6e19dce359d + +""" +Compiled, mashed and generally mutilated 2014-2015 by Denis Pleic +Made available under GNU GENERAL PUBLIC LICENSE + +# Modified Python I2C library for Raspberry Pi +# as found on http://www.recantha.co.uk/blog/?p=4849 +# Joined existing 'i2c_lib.py' and 'lcddriver.py' into a single library +# added bits and pieces from various sources +# By DenisFromHR (Denis Pleic) +# 2015-02-10, ver 0.1 + +""" + +# i2c bus (0 -- original Pi, 1 -- Rev 2 Pi) +I2CBUS = 0 + +# LCD Address +ADDRESS = 0x27 + +import smbus +from time import sleep + +class i2c_device: + def __init__(self, addr, port=I2CBUS): + self.addr = addr + self.bus = smbus.SMBus(port) + +# Write a single command + def write_cmd(self, cmd): + self.bus.write_byte(self.addr, cmd) + sleep(0.0001) + +# Write a command and argument + def write_cmd_arg(self, cmd, data): + self.bus.write_byte_data(self.addr, cmd, data) + sleep(0.0001) + +# Write a block of data + def write_block_data(self, cmd, data): + self.bus.write_block_data(self.addr, cmd, data) + sleep(0.0001) + +# Read a single byte + def read(self): + return self.bus.read_byte(self.addr) + +# Read + def read_data(self, cmd): + return self.bus.read_byte_data(self.addr, cmd) + +# Read a block of data + def read_block_data(self, cmd): + return self.bus.read_block_data(self.addr, cmd) + + +# commands +LCD_CLEARDISPLAY = 0x01 +LCD_RETURNHOME = 0x02 +LCD_ENTRYMODESET = 0x04 +LCD_DISPLAYCONTROL = 0x08 +LCD_CURSORSHIFT = 0x10 +LCD_FUNCTIONSET = 0x20 +LCD_SETCGRAMADDR = 0x40 +LCD_SETDDRAMADDR = 0x80 + +# flags for display entry mode +LCD_ENTRYRIGHT = 0x00 +LCD_ENTRYLEFT = 0x02 +LCD_ENTRYSHIFTINCREMENT = 0x01 +LCD_ENTRYSHIFTDECREMENT = 0x00 + +# flags for display on/off control +LCD_DISPLAYON = 0x04 +LCD_DISPLAYOFF = 0x00 +LCD_CURSORON = 0x02 +LCD_CURSOROFF = 0x00 +LCD_BLINKON = 0x01 +LCD_BLINKOFF = 0x00 + +# flags for display/cursor shift +LCD_DISPLAYMOVE = 0x08 +LCD_CURSORMOVE = 0x00 +LCD_MOVERIGHT = 0x04 +LCD_MOVELEFT = 0x00 + +# flags for function set +LCD_8BITMODE = 0x10 +LCD_4BITMODE = 0x00 +LCD_2LINE = 0x08 +LCD_1LINE = 0x00 +LCD_5x10DOTS = 0x04 +LCD_5x8DOTS = 0x00 + +# flags for backlight control +LCD_BACKLIGHT = 0x08 +LCD_NOBACKLIGHT = 0x00 + +En = 0b00000100 # Enable bit +Rw = 0b00000010 # Read/Write bit +Rs = 0b00000001 # Register select bit + +class lcd: + #initializes objects and lcd + def __init__(self): + self.lcd_device = i2c_device(ADDRESS) + + self.lcd_write(0x03) + self.lcd_write(0x03) + self.lcd_write(0x03) + self.lcd_write(0x02) + + self.lcd_write(LCD_FUNCTIONSET | LCD_2LINE | LCD_5x8DOTS | LCD_4BITMODE) + self.lcd_write(LCD_DISPLAYCONTROL | LCD_DISPLAYON) + self.lcd_write(LCD_CLEARDISPLAY) + self.lcd_write(LCD_ENTRYMODESET | LCD_ENTRYLEFT) + sleep(0.2) + + + # clocks EN to latch command + def lcd_strobe(self, data): + self.lcd_device.write_cmd(data | En | LCD_BACKLIGHT) + sleep(.0005) + self.lcd_device.write_cmd(((data & ~En) | LCD_BACKLIGHT)) + sleep(.0001) + + def lcd_write_four_bits(self, data): + self.lcd_device.write_cmd(data | LCD_BACKLIGHT) + self.lcd_strobe(data) + + # write a command to lcd + def lcd_write(self, cmd, mode=0): + self.lcd_write_four_bits(mode | (cmd & 0xF0)) + self.lcd_write_four_bits(mode | ((cmd << 4) & 0xF0)) + + # write a character to lcd (or character rom) 0x09: backlight | RS=DR< + # works! + def lcd_write_char(self, charvalue, mode=1): + self.lcd_write_four_bits(mode | (charvalue & 0xF0)) + self.lcd_write_four_bits(mode | ((charvalue << 4) & 0xF0)) + + # put string function with optional char positioning + def lcd_display_string(self, string, line=1, pos=0): + if line == 1: + pos_new = pos + elif line == 2: + pos_new = 0x40 + pos + elif line == 3: + pos_new = 0x14 + pos + elif line == 4: + pos_new = 0x54 + pos + + self.lcd_write(0x80 + pos_new) + + for char in string: + self.lcd_write(ord(char), Rs) + + # clear lcd and set to home + def lcd_clear(self): + self.lcd_write(LCD_CLEARDISPLAY) + self.lcd_write(LCD_RETURNHOME) + + # define backlight on/off (lcd.backlight(1); off= lcd.backlight(0) + def backlight(self, state): # for state, 1 = on, 0 = off + if state == 1: + self.lcd_device.write_cmd(LCD_BACKLIGHT) + elif state == 0: + self.lcd_device.write_cmd(LCD_NOBACKLIGHT) + + # add custom characters (0 - 7) + def lcd_load_custom_chars(self, fontdata): + self.lcd_write(0x40); + for char in fontdata: + for line in char: + self.lcd_write_char(line) |