Allow inversion of serial signals

changelog.md

@@ -15,6 +15,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 <!-- ## [Unreleased] -->
 
 ## Released
+## [2.4.0] - 2023-07-20
+### Added
+- The following fixes were provided by @sandyscott
+- UART signals can be inverted with the `invert` argument of the `Serial` and `ModbusRTU` class constructors
+
 ## [2.3.7] - 2023-07-19
 ### Fixed
 - Add a single character wait time after flush to avoid timing issues with RTU control pin, see #68 and #72
@@ -307,8 +312,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - PEP8 style issues on all files of [`lib/uModbus`](lib/uModbus)
 
 <!-- Links -->
-[Unreleased]: https://github.com/brainelectronics/micropython-modbus/compare/2.3.7...develop
+[Unreleased]: https://github.com/brainelectronics/micropython-modbus/compare/2.4.0...develop
 
+[2.4.0]: https://github.com/brainelectronics/micropython-modbus/tree/2.4.0
 [2.3.7]: https://github.com/brainelectronics/micropython-modbus/tree/2.3.7
 [2.3.6]: https://github.com/brainelectronics/micropython-modbus/tree/2.3.6
 [2.3.5]: https://github.com/brainelectronics/micropython-modbus/tree/2.3.5

fakes/machine.py

@@ -27,6 +27,11 @@ class UART(object):
 
     See https://docs.micropython.org/en/latest/library/machine.UART.html
     """
+    # ESP32: TX=32, RX=4
+    # RP2: TX=1, RX=2
+    INV_RX = 4
+    INV_TX = 32
+
     def __init__(self,
                  uart_id: int,
                  baudrate: int = 9600,
@@ -35,7 +40,8 @@ def __init__(self,
                  stop: int = 1,
                  tx: int = 1,
                  rx: int = 2,
-                 timeout: int = 0) -> None:
+                 timeout: int = 0,
+                 invert: int = 0) -> None:
         self._uart_id = uart_id
         if timeout == 0:
             timeout = 5.0

package.json

@@ -38,5 +38,5 @@
         ]
     ],
     "deps": [],
-    "version": "2.3.7"
+    "version": "2.4.0"
 }

umodbus/serial.py

@@ -26,6 +26,10 @@
 
 
 class ModbusRTU(Modbus):
+    # Include in class so they can be used when creating the object
+    INV_RX = UART.INV_RX
+    INV_TX = UART.INV_TX
+
     """
     Modbus RTU client class
 
@@ -45,7 +49,10 @@ class ModbusRTU(Modbus):
     :type       ctrl_pin:    int
     :param      uart_id:     The ID of the used UART
     :type       uart_id:     int
+    :param      invert:      Invert TX and/or RX pins
+    :type       invert:      int
     """
+
     def __init__(self,
                  addr: int,
                  baudrate: int = 9600,
@@ -54,7 +61,8 @@ def __init__(self,
                  parity: Optional[int] = None,
                  pins: List[Union[int, Pin], Union[int, Pin]] = None,
                  ctrl_pin: int = None,
-                 uart_id: int = 1):
+                 uart_id: int = 1,
+                 invert: int = 0):
         super().__init__(
             # set itf to Serial object, addr_list to [addr]
             Serial(uart_id=uart_id,
@@ -63,20 +71,26 @@ def __init__(self,
                    stop_bits=stop_bits,
                    parity=parity,
                    pins=pins,
-                   ctrl_pin=ctrl_pin),
+                   ctrl_pin=ctrl_pin,
+                   invert=invert),
             [addr]
         )
 
 
 class Serial(CommonModbusFunctions):
+    # Include in class so they can be used when creating the object
+    INV_RX = UART.INV_RX
+    INV_TX = UART.INV_TX
+
     def __init__(self,
                  uart_id: int = 1,
                  baudrate: int = 9600,
                  data_bits: int = 8,
                  stop_bits: int = 1,
                  parity=None,
                  pins: List[Union[int, Pin], Union[int, Pin]] = None,
-                 ctrl_pin: int = None):
+                 ctrl_pin: int = None,
+                 invert: int = 0):
         """
         Setup Serial/RTU Modbus
 
@@ -94,6 +108,8 @@ def __init__(self,
         :type       pins:        List[Union[int, Pin], Union[int, Pin]]
         :param      ctrl_pin:    The control pin
         :type       ctrl_pin:    int
+        :param      invert:      Invert TX and/or RX pins
+        :type       invert:      int
         """
         # UART flush function is introduced in Micropython v1.20.0
         self._has_uart_flush = callable(getattr(UART, "flush", None))
@@ -105,7 +121,8 @@ def __init__(self,
                           # timeout_chars=2,  # WiPy only
                           # pins=pins         # WiPy only
                           tx=pins[0],
-                          rx=pins[1]
+                          rx=pins[1],
+                          invert=invert
                           )
 
         if ctrl_pin is not None:

umodbus/version.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
 # -*- coding: UTF-8 -*-
 
-__version_info__ = ("2", "3", "7")
+__version_info__ = ("2", "4", "0")
 __version__ = '.'.join(__version_info__)