Make sure writeto_mem() gets something that supports buffer protocol.

usmbus/__init__.py

@@ -1,3 +1,5 @@
+""" Provides an SMBus class for use on micropython """
+
 try:
     from machine import I2C
 except ImportError:
@@ -7,20 +9,20 @@
 
 class SMBus(I2C):
     """ Provides an 'SMBus' module which supports some of the py-smbus
-        i2c methods, as well as being a subclass of machine.I2C 
+        i2c methods, as well as being a subclass of machine.I2C
 
         Hopefully this will allow you to run code that was targeted at
         py-smbus unmodified on micropython.
- 
-	    Use it like you would the machine.I2C class: 
-    
-            import usmbus.SMBus 
+
+	    Use it like you would the machine.I2C class:
+
+            import usmbus.SMBus
 
             bus = SMBus(1, pins=('G15','G10'), baudrate=100000)
             bus.read_byte_data(addr, register)
-            ... etc	
+            ... etc
 	"""
-    
+
     def read_byte_data(self, addr, register):
         """ Read a single byte from register of device at addr
             Returns a single byte """
@@ -32,29 +34,35 @@ def read_i2c_block_data(self, addr, register, length):
         return self.readfrom_mem(addr, register, length)
 
     def write_byte_data(self, addr, register, data):
-        """ Write a single byte of data to register of device at addr
+        """ Write a single byte from buffer `data` to register of device at addr
             Returns None """
+        # writeto_mem() expects something it can treat as a buffer
+        if isinstance(data, int):
+            data = bytes([data])
         return self.writeto_mem(addr, register, data)
 
     def write_i2c_block_data(self, addr, register, data):
         """ Write multiple bytes of data to register of device at addr
             Returns None """
+        # writeto_mem() expects something it can treat as a buffer
+        if isinstance(data, int):
+            data = bytes([data])
         return self.writeto_mem(addr, register, data)
-    
+
     # The follwing haven't been implemented, but could be.
-    def read_byte(*args, **kwargs):
+    def read_byte(self, *args, **kwargs):
         """ Not yet implemented """
         raise RuntimeError("Not yet implemented")
 
-    def write_byte(*args, **kwargs):
+    def write_byte(self, *args, **kwargs):
         """ Not yet implemented """
         raise RuntimeError("Not yet implemented")
 
-    def read_word_data(*args, **kwargs):
+    def read_word_data(self, *args, **kwargs):
         """ Not yet implemented """
         raise RuntimeError("Not yet implemented")
 
-    def write_word_data(*args, **kwargs):
+    def write_word_data(self, *args, **kwargs):
         """ Not yet implemented """
         raise RuntimeError("Not yet implemented")
-
+