1 files changed, 68 insertions, 0 deletions

diff --git a/bin/hardware_driver.py b/bin/hardware_driver.py
new file mode 100644
index 0000000..1afb219
--- /dev/null
+++ b/bin/hardware_driver.py
@@ -0,0 +1,68 @@
+from smbus2 import SMBus
+from time import sleep
+
+ALIGN_FUNC = {"left": "ljust", "right": "rjust", "center": "center"}
+CLEAR_DISPLAY = 0x01
+ENABLE_BIT = 0b00000100
+LINES = {1: 0x80, 2: 0xC0, 3: 0x94, 4: 0xD4}
+
+LCD_BACKLIGHT = 0x08
+LCD_NOBACKLIGHT = 0x00
+
+
+class LCD(object):
+
+    def __init__(self, address=0x27, bus=1, width=20, rows=4, backlight=True):
+        self.address = address
+        self.bus = SMBus(bus)
+        self.delay = 0.0005
+        self.rows = rows
+        self.width = width
+        self.backlight_status = backlight
+
+        self.write(0x33)
+        self.write(0x32)
+        self.write(0x06)
+        self.write(0x0C)
+        self.write(0x28)
+        self.write(CLEAR_DISPLAY)
+        sleep(self.delay)
+
+    def _write_byte(self, byte):
+        self.bus.write_byte(self.address, byte)
+        self.bus.write_byte(self.address, (byte | ENABLE_BIT))
+        sleep(self.delay)
+        self.bus.write_byte(self.address, (byte & ~ENABLE_BIT))
+        sleep(self.delay)
+
+    def write(self, byte, mode=0):
+        backlight_mode = LCD_BACKLIGHT if self.backlight_status else LCD_NOBACKLIGHT
+        self._write_byte(mode | (byte & 0xF0) | backlight_mode)
+        self._write_byte(mode | ((byte << 4) & 0xF0) | backlight_mode)
+
+    def text(self, text, line, align="left"):
+        self.write(LINES.get(line, LINES[1]))
+        text, other_lines = self.get_text_line(text)
+        text = getattr(text, ALIGN_FUNC.get(align, "ljust"))(self.width)
+        for char in text:
+            self.write(ord(char), mode=1)
+        if other_lines and line <= self.rows - 1:
+            self.text(other_lines, line + 1, align=align)
+
+    def backlight(self, turn_on=True):
+        self.backlight_status = turn_on
+        self.write(0)
+
+    def get_text_line(self, text):
+        line_break = self.width
+        if len(text) > self.width:
+            line_break = text[: self.width + 1].rfind(" ")
+        if line_break < 0:
+            line_break = self.width
+        return text[:line_break], text[line_break:].strip()
+
+    def clear(self):
+        self.write(CLEAR_DISPLAY)
+
+    def read(self):
+        self._read_i2c_block_data