Add multiplexing switch

cd4052.py

@@ -0,0 +1,79 @@
+"""MicroPython CD4052B Analog Multiplexer driver
+
+Driver for the 8-channel analog multiplexer with logic-level conversion from
+Texas Instruments. (https://www.ti.com/lit/ds/symlink/cd4051b.pdf)
+
+The CD4052B switches up to four pairs of inputs or outputs, numbered 0 through
+3, mapping them to the two common pins.
+
+Copyright 2023 Correl Roush
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the “Software”), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+"""
+
+
+from machine import Pin
+
+
+class CD4052:
+    def __init__(self, channel_select_a: int, channel_select_b: int, inh: int):
+        self._channel_select_a = Pin(channel_select_a, Pin.OUT)
+        self._channel_select_b = Pin(channel_select_b, Pin.OUT)
+        self._inh = Pin(inh, Pin.OUT)
+
+    def select(self, channel: int) -> None:
+        """Select a channel pair between 0 and 3.
+
+        The device will be muted during the switch. Mute will be re-enabled once
+        the switch is complete if the device wasn't already muted.
+
+        """
+        a = channel & 0b01
+        b = (channel & 0b10) >> 1
+        print(f"CD4052: Selecting Channel {channel} ({a}, {b})")
+        mute = self._inh()
+        self._inh.on()
+        self._channel_select_a(a)
+        self._channel_select_b(b)
+        self._inh(mute)
+
+    def channel(self) -> int:
+        """Retrieve the currently selected channel pair."""
+        return self._channel_select_a() | (self._channel_select_b() << 1)
+
+    def muted(self) -> bool:
+        """Return the mute status."""
+        return bool(self._inh())
+
+    def mute(self, value: bool = True) -> None:
+        """Mute the device."""
+        self._inh(value)
+
+    def unmute(self) -> None:
+        """Unmute the device."""
+        self._inh(False)
+
+    def toggle_mute(self) -> None:
+        """Togggle mute."""
+        self._inh(not self._inh())
+
+
+if __name__ == "__main__":
+    switch = CD4052(18, 19, 23)
+    switch.select(0)

main.py

@@ -8,6 +8,7 @@ import utime
 
 from umqtt.simple import MQTTClient
 
+import cd4052
 import ssd1306
 import mcp4
 from rotary_irq_esp import RotaryIRQ
@@ -25,7 +26,9 @@ state = StateTree(
         "volume": {
             "left": 0,
             "right": 0,
+            "muted": False,
         },
+        "channel": 0,
     }
 )
 last_update = 0
@@ -49,6 +52,9 @@ except Exception as e:
     print("WARNING: OLED unavailable:", e)
     oled = None
 
+switch = cd4052.CD4052(18, 19, 23)
+switch.select(state["channel"])
+
 sta_if = network.WLAN(network.STA_IF)
 
 spi = SPI(1)
@@ -75,6 +81,10 @@ def on_message(topic, msg):
             pot.write(0, volume["left"])
         if isinstance(volume.get("right"), int):
             pot.write(1, volume["right"])
+        if isinstance(volume.get("muted"), bool):
+            switch.mute(volume["muted"])
+    if isinstance(msg.get("channel"), int):
+        switch.select(msg["channel"])
 
 
 def loop():
@@ -82,6 +92,8 @@ def loop():
 
     state["volume"]["left"] = pot.read(0)
     state["volume"]["right"] = pot.read(1)
+    state["volume"]["muted"] = switch.muted()
+    state["channel"] = switch.channel()
 
     if state.changed:
         # Volume changed externally