fix: correct PWM output mode register logic and add RPM noise filtering

- Fix PWM output config (0x2B): 0=open-drain (default), 1=push-pull
  Previous implementation had this inverted
- Add MIN_VALID_RPM_READING constant (200 RPM) to filter tach noise
- Filter RPM readings below threshold as stopped fan (return 0)
- Add PWM output mode API: set_pwm_output_mode(), set_all_pwm_output_mode(),
  get_pwm_output_mode()
- Add PWM polarity API: set_pwm_polarity(), get_pwm_polarity()

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: moffa90

CHANGELOG.md

@@ -10,6 +10,30 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Nothing yet
 
+## [1.1.0] - 2025-11-25
+
+### Added
+- `set_pwm_output_mode()` - Configure PWM output as open-drain or push-pull per channel
+- `set_all_pwm_output_mode()` - Configure PWM output mode for all channels at once
+- `get_pwm_output_mode()` - Read current PWM output mode for a channel
+- `set_pwm_polarity()` - Configure PWM polarity (normal/inverted) per channel
+- `get_pwm_polarity()` - Read current PWM polarity for a channel
+- `MIN_VALID_RPM_READING` constant (200 RPM) for tachometer noise filtering
+
+### Fixed
+- **Critical**: PWM output mode register (0x2B) logic was inverted. Per datasheet: 0=open-drain (default), 1=push-pull. Previous implementation had this backwards.
+- RPM readings below 200 RPM now return 0 (filters tachometer noise when fan is stopped)
+
+## [1.0.0] - 2025-11-25
+
+### Added
+- PyPI publishing workflow with trusted publishing (OIDC)
+- Donation section in README
+
+### Changed
+- Package published to PyPI as `microchip-emc2305`
+- Removed phase/roadmap references from documentation
+
 ## [0.1.0] - 2025-11-24
 
 ### Added
@@ -64,5 +88,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Contributing guidelines
 - MIT License
 
-[Unreleased]: https://github.com/moffa90/python-emc2305/compare/v0.1.0...HEAD
+[Unreleased]: https://github.com/moffa90/python-emc2305/compare/v1.1.0...HEAD
+[1.1.0]: https://github.com/moffa90/python-emc2305/compare/v1.0.0...v1.1.0
+[1.0.0]: https://github.com/moffa90/python-emc2305/compare/v0.1.0...v1.0.0
 [0.1.0]: https://github.com/moffa90/python-emc2305/releases/tag/v0.1.0

emc2305/driver/constants.py

@@ -97,8 +97,16 @@
 DEFAULT_PWM_POLARITY = 0x00
 """Default PWM polarity configuration (normal/non-inverted for all channels)"""
 
-DEFAULT_PWM_OUTPUT_CONFIG = 0x1F
-"""Default PWM output configuration (open-drain for all channels) - Recommended by electronics engineer for better signal integrity"""
+DEFAULT_PWM_OUTPUT_CONFIG = 0x00
+"""Default PWM output configuration (open-drain for all channels, per datasheet default)"""
+
+# PWM Output Type Constants (Register 0x2B bit values)
+# Datasheet: '0' (default) = open drain, '1' = push-pull
+PWM_OUTPUT_OPEN_DRAIN = 0
+"""Open-drain output mode (default, requires external pull-up resistor)"""
+
+PWM_OUTPUT_PUSH_PULL = 1
+"""Push-pull output mode (active drive high and low)"""
 
 FAN_INTERRUPT_ENABLE_ALL_FANS = 0x1F
 """Enable interrupts for all 5 fan channels (bits 4-0 set)"""
@@ -444,6 +452,9 @@
 MIN_RPM = 500
 """Minimum supported RPM (hardware limit)"""
 
+MIN_VALID_RPM_READING = 200
+"""RPM readings below this threshold are considered noise (fan stopped)"""
+
 MAX_RPM = 16000
 """Maximum supported RPM with internal clock (500-16k range)"""
 

emc2305/driver/emc2305.py

@@ -936,6 +936,161 @@ def set_pwm_duty_cycle_verified(
 
         return (False, actual)
 
+    def set_pwm_output_mode(self, channel: int, open_drain: bool = True) -> None:
+        """
+        Set PWM output mode for a specific fan channel.
+
+        Args:
+            channel: Fan channel number (1-5)
+            open_drain: True for open-drain (default), False for push-pull
+
+        Note:
+            - Open-drain (default): Requires external pull-up resistor. Better for
+              level shifting and shared bus scenarios.
+            - Push-pull: Active drive high and low. No external pull-up needed.
+
+        Example:
+            >>> fan_controller.set_pwm_output_mode(1, open_drain=True)   # Open-drain
+            >>> fan_controller.set_pwm_output_mode(1, open_drain=False)  # Push-pull
+        """
+        self._validate_channel(channel)
+
+        with self._lock:
+            try:
+                # Read current config
+                current = self.i2c_bus.read_byte(self.address, const.REG_PWM_OUTPUT_CONFIG)
+
+                # Per datasheet: 0 = open-drain (default), 1 = push-pull
+                bit_mask = 1 << (channel - 1)
+
+                if open_drain:
+                    new_config = current & ~bit_mask  # Clear bit for open-drain
+                else:
+                    new_config = current | bit_mask   # Set bit for push-pull
+
+                self.i2c_bus.write_byte(self.address, const.REG_PWM_OUTPUT_CONFIG, new_config)
+                logger.debug(
+                    f"Fan {channel} PWM output set to {'open-drain' if open_drain else 'push-pull'}"
+                )
+
+            except I2CError as e:
+                raise EMC2305Error(f"Failed to set PWM output mode for fan {channel}: {e}")
+
+    def set_all_pwm_output_mode(self, open_drain: bool = True) -> None:
+        """
+        Set PWM output mode for all fan channels.
+
+        Args:
+            open_drain: True for open-drain (default), False for push-pull
+
+        Example:
+            >>> fan_controller.set_all_pwm_output_mode(open_drain=True)   # All open-drain
+            >>> fan_controller.set_all_pwm_output_mode(open_drain=False)  # All push-pull
+        """
+        with self._lock:
+            try:
+                # Per datasheet: 0 = open-drain, 1 = push-pull
+                config = 0x00 if open_drain else 0x1F
+                self.i2c_bus.write_byte(self.address, const.REG_PWM_OUTPUT_CONFIG, config)
+                logger.debug(
+                    f"All PWM outputs set to {'open-drain' if open_drain else 'push-pull'}"
+                )
+
+            except I2CError as e:
+                raise EMC2305Error(f"Failed to set PWM output mode: {e}")
+
+    def get_pwm_output_mode(self, channel: int) -> bool:
+        """
+        Get PWM output mode for a specific fan channel.
+
+        Args:
+            channel: Fan channel number (1-5)
+
+        Returns:
+            True if open-drain, False if push-pull
+
+        Example:
+            >>> is_open_drain = fan_controller.get_pwm_output_mode(1)
+            >>> print("Open-drain" if is_open_drain else "Push-pull")
+        """
+        self._validate_channel(channel)
+
+        with self._lock:
+            try:
+                config = self.i2c_bus.read_byte(self.address, const.REG_PWM_OUTPUT_CONFIG)
+                bit_mask = 1 << (channel - 1)
+                # Per datasheet: 0 = open-drain, 1 = push-pull
+                # Return True for open-drain (bit NOT set)
+                return not bool(config & bit_mask)
+
+            except I2CError as e:
+                raise EMC2305Error(f"Failed to read PWM output mode for fan {channel}: {e}")
+
+    def set_pwm_polarity(self, channel: int, inverted: bool = False) -> None:
+        """
+        Set PWM polarity for a specific fan channel.
+
+        Args:
+            channel: Fan channel number (1-5)
+            inverted: True for inverted (100% = fan off), False for normal (100% = fan max)
+
+        Note:
+            - Normal polarity (default): 0% duty = fan off, 100% duty = fan max speed
+            - Inverted polarity: 0% duty = fan max speed, 100% duty = fan off
+            Check your fan's datasheet to determine the correct polarity.
+
+        Example:
+            >>> fan_controller.set_pwm_polarity(1, inverted=False)  # Normal
+            >>> fan_controller.set_pwm_polarity(1, inverted=True)   # Inverted
+        """
+        self._validate_channel(channel)
+
+        with self._lock:
+            try:
+                # Read current config
+                current = self.i2c_bus.read_byte(self.address, const.REG_PWM_POLARITY_CONFIG)
+
+                # Each channel is 1 bit: 0 = normal, 1 = inverted
+                bit_mask = 1 << (channel - 1)
+
+                if inverted:
+                    new_config = current | bit_mask
+                else:
+                    new_config = current & ~bit_mask
+
+                self.i2c_bus.write_byte(self.address, const.REG_PWM_POLARITY_CONFIG, new_config)
+                logger.debug(
+                    f"Fan {channel} PWM polarity set to {'inverted' if inverted else 'normal'}"
+                )
+
+            except I2CError as e:
+                raise EMC2305Error(f"Failed to set PWM polarity for fan {channel}: {e}")
+
+    def get_pwm_polarity(self, channel: int) -> bool:
+        """
+        Get PWM polarity for a specific fan channel.
+
+        Args:
+            channel: Fan channel number (1-5)
+
+        Returns:
+            True if inverted, False if normal
+
+        Example:
+            >>> is_inverted = fan_controller.get_pwm_polarity(1)
+            >>> print("Inverted" if is_inverted else "Normal")
+        """
+        self._validate_channel(channel)
+
+        with self._lock:
+            try:
+                config = self.i2c_bus.read_byte(self.address, const.REG_PWM_POLARITY_CONFIG)
+                bit_mask = 1 << (channel - 1)
+                return bool(config & bit_mask)
+
+            except I2CError as e:
+                raise EMC2305Error(f"Failed to read PWM polarity for fan {channel}: {e}")
+
     # =============================================================================
     # Public API - RPM Control (FSC Mode)
     # =============================================================================
@@ -1060,6 +1215,10 @@ def get_current_rpm(self, channel: int) -> int:
                 config = self._fan_configs.get(channel, FanConfig())
                 rpm = self._tach_count_to_rpm(tach_count, config.edges)
 
+                # Filter noise - readings below threshold mean fan is stopped
+                if rpm < const.MIN_VALID_RPM_READING:
+                    return 0
+
                 return rpm
 
             except I2CError as e:

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "microchip-emc2305"
-version = "1.0.0"
+version = "1.1.0"
 description = "Python driver for Microchip EMC2305 5-channel PWM fan controller"
 readme = "README.md"
 authors = [