Upload files to "lib"

2026-01-18 11:49:44 +00:00
parent d556f78fd3
commit 3543ed1db6
2 changed files with 272 additions and 0 deletions
@@ -0,0 +1,86 @@
+import utime
+import gc
+
+from lcd_api import LcdApi
+from machine import I2C
+
+# PCF8574 pin definitions
+MASK_RS = 0x01       # P0
+MASK_RW = 0x02       # P1
+MASK_E  = 0x04       # P2
+
+SHIFT_BACKLIGHT = 3  # P3
+SHIFT_DATA      = 4  # P4-P7
+
+class I2cLcd(LcdApi):
+    
+    #Implements a HD44780 character LCD connected via PCF8574 on I2C
+
+    def __init__(self, i2c, i2c_addr, num_lines, num_columns):
+        self.i2c = i2c
+        self.i2c_addr = i2c_addr
+        self.i2c.writeto(self.i2c_addr, bytes([0]))
+        utime.sleep_ms(20)   # Allow LCD time to powerup
+        # Send reset 3 times
+        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
+        utime.sleep_ms(5)    # Need to delay at least 4.1 msec
+        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
+        utime.sleep_ms(1)
+        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
+        utime.sleep_ms(1)
+        # Put LCD into 4-bit mode
+        self.hal_write_init_nibble(self.LCD_FUNCTION)
+        utime.sleep_ms(1)
+        LcdApi.__init__(self, num_lines, num_columns)
+        cmd = self.LCD_FUNCTION
+        if num_lines > 1:
+            cmd |= self.LCD_FUNCTION_2LINES
+        self.hal_write_command(cmd)
+        gc.collect()
+
+    def hal_write_init_nibble(self, nibble):
+        # Writes an initialization nibble to the LCD.
+        # This particular function is only used during initialization.
+        byte = ((nibble >> 4) & 0x0f) << SHIFT_DATA
+        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
+        self.i2c.writeto(self.i2c_addr, bytes([byte]))
+        gc.collect()
+        
+    def hal_backlight_on(self):
+        # Allows the hal layer to turn the backlight on
+        self.i2c.writeto(self.i2c_addr, bytes([1 << SHIFT_BACKLIGHT]))
+        gc.collect()
+        
+    def hal_backlight_off(self):
+        #Allows the hal layer to turn the backlight off
+        self.i2c.writeto(self.i2c_addr, bytes([0]))
+        gc.collect()
+        
+    def hal_write_command(self, cmd):
+        # Write a command to the LCD. Data is latched on the falling edge of E.
+        byte = ((self.backlight << SHIFT_BACKLIGHT) |
+                (((cmd >> 4) & 0x0f) << SHIFT_DATA))
+        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
+        self.i2c.writeto(self.i2c_addr, bytes([byte]))
+        byte = ((self.backlight << SHIFT_BACKLIGHT) |
+                ((cmd & 0x0f) << SHIFT_DATA))
+        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
+        self.i2c.writeto(self.i2c_addr, bytes([byte]))
+        if cmd <= 3:
+            # The home and clear commands require a worst case delay of 4.1 msec
+            utime.sleep_ms(5)
+        gc.collect()
+
+    def hal_write_data(self, data):
+        # Write data to the LCD. Data is latched on the falling edge of E.
+        byte = (MASK_RS |
+                (self.backlight << SHIFT_BACKLIGHT) |
+                (((data >> 4) & 0x0f) << SHIFT_DATA))
+        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
+        self.i2c.writeto(self.i2c_addr, bytes([byte]))
+        byte = (MASK_RS |
+                (self.backlight << SHIFT_BACKLIGHT) |
+                ((data & 0x0f) << SHIFT_DATA))      
+        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
+        self.i2c.writeto(self.i2c_addr, bytes([byte]))
+        gc.collect()