Merge pull request #17 from fourstix/b_revert

Revert write_then_readinto to write() folowed by read()

Author: fourstix

README.rst

@@ -154,6 +154,23 @@ Usage Example
     # For a different address use QwiicTwist(i2c, address)
     # twist = QwiicTwist(i2c, 0x3E)
 
+Upgrading
+=========
+On supported GNU/Linux systems like the Raspberry Pi, you can upgrade the driver
+to the latest published version.
+
+To upgrade for current user:
+
+.. code-block:: shell
+
+    pip3 install --upgrade sparkfun-circuitpython-qwiicjoystick
+
+To upgrade system-wide (this may be required in some cases):
+
+.. code-block:: shell
+
+    sudo pip3 install --upgrade sparkfun-circuitpython-qwiicjoystick
+
 Contributing
 ============
 

sparkfun_qwiictwist.py

@@ -352,8 +352,12 @@ def change_address(self, new_address: int) -> bool:
     def _read_register8(self, addr: int) -> int:
         # Read and return a byte from the specified 8-bit register address.
         with self._device as device:
+            device.write(bytes([addr & 0xFF]))
             result = bytearray(1)
-            device.write_then_readinto(bytes([addr & 0xFF]), result)
+            # write_then_readinto() does not work reliably,
+            # so do explicit write followed by read into
+            # device.write_then_readinto(bytes([addr & 0xFF]), result)
+            device.readinto(result)
             if self._debug:
                 print("$%02X => %s" % (addr, [hex(i) for i in result]))
             return result[0]
@@ -368,8 +372,12 @@ def _write_register8(self, addr: int, value: int) -> None:
     def _read_register16(self, addr: int) -> int:
         # Read and return a 16-bit value from the specified 8-bit register address.
         with self._device as device:
+            device.write(bytes([addr & 0xFF]))
             result = bytearray(2)
-            device.write_then_readinto(bytes([addr & 0xFF]), result)
+            # write_then_readinto() does not work reliably,
+            # so do explicit write followed by read into
+            # device.write_then_readinto(bytes([addr & 0xFF]), result)
+            device.readinto(result)
             if self._debug:
                 print("$%02X => %s" % (addr, [hex(i) for i in result]))
             return (result[1] << 8) | result[0]