290 lines
9.9 KiB
Python
290 lines
9.9 KiB
Python
# Copyright (C) 2017 Dan Halbert
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# Adapted from https://github.com/dbrgn/RPLCD, Copyright (C) 2013-2016 Danilo Bargen
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# Permission is hereby granted, free of charge, to any person obtaining a copy of
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# this software and associated documentation files (the "Software"), to deal in
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# the Software without restriction, including without limitation the rights to
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# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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# the Software, and to permit persons to whom the Software is furnished to do so,
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# subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in all
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# copies or substantial portions of the Software.
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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import time
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from micropython import const
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# Commands
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_LCD_CLEARDISPLAY = const(0x01)
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_LCD_RETURNHOME = const(0x02)
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_LCD_ENTRYMODESET = const(0x04)
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_LCD_DISPLAYCONTROL = const(0x08)
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_LCD_CURSORSHIFT = const(0x10)
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_LCD_FUNCTIONSET = const(0x20)
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_LCD_SETCGRAMADDR = const(0x40)
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_LCD_SETDDRAMADDR = const(0x80)
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# Flags for display entry mode
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_LCD_ENTRYRIGHT = const(0x00)
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_LCD_ENTRYLEFT = const(0x02)
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_LCD_ENTRYSHIFTINCREMENT = const(0x01)
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_LCD_ENTRYSHIFTDECREMENT = const(0x00)
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# Flags for display on/off control
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_LCD_DISPLAYON = const(0x04)
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_LCD_DISPLAYOFF = const(0x00)
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_LCD_CURSORON = const(0x02)
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_LCD_CURSOROFF = const(0x00)
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_LCD_BLINKON = const(0x01)
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_LCD_BLINKOFF = const(0x00)
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# Flags for display/cursor shift
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_LCD_DISPLAYMOVE = const(0x08)
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_LCD_CURSORMOVE = const(0x00)
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_LCD_MOVERIGHT = const(0x04)
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_LCD_MOVELEFT = const(0x00)
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# Flags for function set
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_LCD_8BITMODE = const(0x10)
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LCD_4BITMODE = const(0x00)
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_LCD_2LINE = const(0x08)
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_LCD_1LINE = const(0x00)
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_LCD_5x10DOTS = const(0x04)
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_LCD_5x8DOTS = const(0x00)
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# Flags for backlight control
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LCD_BACKLIGHT = const(0x08)
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LCD_NOBACKLIGHT = const(0x00)
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# Flags for RS pin modes
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_RS_INSTRUCTION = const(0x00)
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_RS_DATA = const(0x01)
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# Pin bitmasks
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PIN_ENABLE = const(0x4)
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PIN_READ_WRITE = const(0x2)
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PIN_REGISTER_SELECT = const(0x1)
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class CursorMode:
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HIDE = const(_LCD_CURSOROFF | _LCD_BLINKOFF)
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LINE = const(_LCD_CURSORON | _LCD_BLINKOFF)
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BLINK = const(_LCD_CURSOROFF | _LCD_BLINKON)
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MICROSECOND = 1e-6
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MILLISECOND = 1e-3
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class LCD(object):
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def __init__(self, interface, num_cols=20, num_rows=4, char_height=8):
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"""
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Character LCD controller.
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:param interface: Communication interface, such as I2CInterface
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:param num_rows: Number of display rows (usually 1, 2 or 4). Default: 4.
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:param num_cols: Number of columns per row (usually 16 or 20). Default 20.
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:param char_height: Some 1 line displays allow a font height of 10px.
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Allowed: 8 or 10. Default: 8.
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"""
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self.interface = interface
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if char_height not in (8, 10):
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raise ValueError('The ``char_height`` argument should be either 8 or 10.')
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self.char_height = char_height
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self.num_rows = num_rows
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self.num_cols = num_cols
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# get row addresses (varies based on display size)
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self._row_offsets = (0x00, 0x40, self.num_cols, 0x40 + self.num_cols)
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# Setup initial display configuration
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displayfunction = self.interface.data_bus_mode | _LCD_5x8DOTS
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if self.num_rows == 1:
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displayfunction |= _LCD_1LINE
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elif self.num_rows in (2, 4):
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# LCD only uses two lines on 4 row displays
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displayfunction |= _LCD_2LINE
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if self.char_height == 10:
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# For some 1 line displays you can select a 10px font.
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displayfunction |= _LCD_5x10DOTS
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# Choose 4 or 8 bit mode
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self.command(0x03)
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time.sleep(4.5*MILLISECOND)
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self.command(0x03)
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time.sleep(4.5*MILLISECOND)
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self.command(0x03)
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if self.interface.data_bus_mode == LCD_4BITMODE:
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# Hitachi manual page 46
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time.sleep(100*MICROSECOND)
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self.command(0x02)
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elif self.interface.data_bus_mode == _LCD_8BITMODE:
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# Hitachi manual page 45
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self.command(0x30)
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time.sleep(4.5*MILLISECOND)
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self.command(0x30)
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time.sleep(100*MICROSECOND)
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self.command(0x30)
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else:
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raise ValueError('Invalid data bus mode: {}'.format(self.interface.data_bus_mode))
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# Write configuration to display
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self.command(_LCD_FUNCTIONSET | displayfunction)
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time.sleep(50*MICROSECOND)
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# Configure entry mode. Define internal fields.
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self.command(_LCD_ENTRYMODESET | _LCD_ENTRYLEFT)
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time.sleep(50*MICROSECOND)
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# Configure display mode. Define internal fields.
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self._display_mode = _LCD_DISPLAYON
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self._cursor_mode = CursorMode.HIDE
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self.command(_LCD_DISPLAYCONTROL | self._display_mode | self._cursor_mode)
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time.sleep(50*MICROSECOND)
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self.clear()
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def close(self):
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self.interface.deinit()
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def set_backlight(self, value):
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self.interface.backlight = value
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def set_display_enabled(self, value):
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self._display_mode = _LCD_DISPLAYON if value else _LCD_DISPLAYOFF
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self.command(_LCD_DISPLAYCONTROL | self._display_mode | self._cursor_mode)
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time.sleep(50*MICROSECOND)
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def set_cursor_mode(self, value):
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self._cursor_mode = value
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self.command(_LCD_DISPLAYCONTROL | self._display_mode | self._cursor_mode)
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time.sleep(50*MICROSECOND)
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def cursor_pos(self):
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"""The cursor position as a 2-tuple (row, col)."""
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return (self._row, self._col)
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def set_cursor_pos(self, row, col):
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if not (0 <= row < self.num_rows):
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raise ValueError('row should be in range 0-{}'.format(self.num_rows - 1))
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if not (0 <= col < self.num_cols):
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raise ValueError('col should be in range 0-{}'.format(self.num_cols - 1))
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self._row = row
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self._col = col
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self.command(_LCD_SETDDRAMADDR | self._row_offsets[row] + col)
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time.sleep(50*MICROSECOND)
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def print(self, string):
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"""
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Write the specified unicode string to the display.
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A newline ('\n') will advance to the left side of the next row.
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Lines that are too long automatically continue on next line.
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Only characters with an ``ord()`` value between 0 and 255 are currently
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supported.
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"""
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for char in string:
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if char == '\n':
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# Advance to next row, at left side. Wrap around to top row if at bottom.
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self.set_cursor_pos((self._row + 1) % self.num_rows, 0)
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else:
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self.write(ord(char))
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def clear(self):
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"""Overwrite display with blank characters and reset cursor position."""
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self.command(_LCD_CLEARDISPLAY)
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time.sleep(2*MILLISECOND)
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self.home()
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def home(self):
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"""Set cursor to initial position and reset any shifting."""
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self.command(_LCD_RETURNHOME)
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self._row = 0
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self._col = 0
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time.sleep(2*MILLISECOND)
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def shift_display(self, amount):
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"""Shift the display. Use negative amounts to shift left and positive
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amounts to shift right."""
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if amount == 0:
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return
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direction = _LCD_MOVERIGHT if amount > 0 else _LCD_MOVELEFT
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for i in range(abs(amount)):
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self.command(_LCD_CURSORSHIFT | _LCD_DISPLAYMOVE | direction)
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time.sleep(50*MICROSECOND)
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def create_char(self, location, bitmap):
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"""Create a new character.
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The HD44780 supports up to 8 custom characters (location 0-7).
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:param location: The place in memory where the character is stored.
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Values need to be integers between 0 and 7.
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:type location: int
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:param bitmap: The bitmap containing the character. This should be a
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bytearray of 8 numbers, each representing a 5 pixel row.
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:type bitmap: bytearray
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:raises AssertionError: Raised when an invalid location is passed in or
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when bitmap has an incorrect size.
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Example:
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.. sourcecode:: python
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>>> smiley = bytearray(
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... 0b00000,
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... 0b01010,
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... 0b01010,
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... 0b00000,
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... 0b10001,
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... 0b10001,
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... 0b01110,
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... 0b00000,
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... )
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>>> lcd.create_char(0, smiley)
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"""
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if not (0 <= location <= 7):
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raise ValueError('Only locations 0-7 are valid.')
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if len(bitmap) != 8:
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raise ValueError('Bitmap should have exactly 8 rows.')
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# Store previous position
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save_row = self._row
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save_col = self._col
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# Write character to CGRAM
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self.command(_LCD_SETCGRAMADDR | location << 3)
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for row in bitmap:
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self.interface.send(row, _RS_DATA)
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# Restore cursor pos
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self.set_cursor_pos(save_row, save_col)
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def command(self, value):
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"""Send a raw command to the LCD."""
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self.interface.send(value, _RS_INSTRUCTION)
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def write(self, value):
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"""Write a raw character byte to the LCD."""
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self.interface.send(value, _RS_DATA)
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if self._col < self.num_cols - 1:
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# Char was placed on current line. No need to reposition cursor.
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self._col += 1
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else:
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# At end of line: go to left side next row. Wrap around to first row if on last row.
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self._row = (self._row + 1) % self.num_rows
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self._col = 0
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self.set_cursor_pos(self._row, self._col)
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