Fix the problem (#2)

Author: funnygeeker

driver/st7735_buf.mpy

@@ -144,7 +144,7 @@ def __init__(self, width: int, height: int, spi, res: int, dc: int,
             self.cs = Pin(cs, Pin.OUT, Pin.PULL_DOWN)
         if bl is not None:
             self.bl = PWM(Pin(bl, Pin.OUT))
-            self.bl.duty_u16(1023)
+            self.back_light(255)
         else:
             self.bl = None
         self._rotate = rotate

driver/st7735_buf.py

@@ -142,7 +142,7 @@ def __init__(self, width: int, height: int, spi, res: int, dc: int,
             self.cs = Pin(cs, Pin.OUT, Pin.PULL_DOWN)
         if bl is not None:
             self.bl = PWM(Pin(bl, Pin.OUT))
-            self.bl.duty_u16(1023)
+            self.back_light(255)
         else:
             self.bl = None
         self._rotate = rotate

driver/st7735_spi.mpy

@@ -179,7 +179,7 @@ def __init__(self, width: int, height: int, spi, res: int, dc: int,
             self.cs = Pin(cs, Pin.OUT, Pin.PULL_DOWN)
         if bl is not None:
             self.bl = PWM(Pin(bl, Pin.OUT))
-            self.bl.duty_u16(1023)
+            self.back_light(255)
         else:
             self.bl = None
         self._rotate = rotate

driver/st7735_spi.py

@@ -177,7 +177,7 @@ def __init__(self, width: int, height: int, spi, res: int, dc: int,
             self.cs = Pin(cs, Pin.OUT, Pin.PULL_DOWN)
         if bl is not None:
             self.bl = PWM(Pin(bl, Pin.OUT))
-            self.bl.duty_u16(1023)
+            self.back_light(255)
         else:
             self.bl = None
         self._rotate = rotate