Merge newly created modules to main

Communication/PCAL6416A/PCAL6416A/Examples/pcal6416a-digitalRead.py

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+# FILE: pcal6416a-digitalRead.py
+# AUTHOR: Fran Fodor @ Soldered
+# BRIEF: Read the state of a pin with an internal pull-up using the PCAL6416A IO expander.
+#        Connect a pushbutton between pin A0 and GND — pressing it pulls the pin LOW.
+# WORKS WITH: PCAL6416A IO Expander breakout: www.solde.red/333351
+# LAST UPDATED: 2026-04-23
+
+import time
+from machine import Pin, I2C
+from pcal6416a import PCAL6416A, PCAL6416A_A0, INPUT_PULLUP
+
+# If you aren't using the Qwiic connector, manually enter your I2C pins:
+# i2c = I2C(0, scl=Pin(22), sda=Pin(21))
+# expander = PCAL6416A(i2c)
+
+# Initialize expander over Qwiic
+expander = PCAL6416A()
+
+# Set pin A0 as input with internal pull-up (pin reads HIGH when button is open)
+expander.pinMode(PCAL6416A_A0, INPUT_PULLUP)
+
+while True:
+    state = expander.digitalRead(PCAL6416A_A0)
+    print("State of pin A0 is: {}".format("HIGH" if state else "LOW"))
+    time.sleep(1)

Communication/PCAL6416A/PCAL6416A/Examples/pcal6416a-digitalWrite.py

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+# FILE: pcal6416a-digitalWrite.py
+# AUTHOR: Fran Fodor @ Soldered
+# BRIEF: Blink an output pin on the PCAL6416A IO expander.
+#        Connect an LED (with series resistor) between pin A0 and GND.
+# WORKS WITH: PCAL6416A IO Expander breakout: www.solde.red/333351
+# LAST UPDATED: 2026-04-23
+
+import time
+from machine import Pin, I2C
+from pcal6416a import PCAL6416A, PCAL6416A_A0, OUTPUT
+
+# If you aren't using the Qwiic connector, manually enter your I2C pins:
+# i2c = I2C(0, scl=Pin(22), sda=Pin(21))
+# expander = PCAL6416A(i2c)
+
+# Initialize expander over Qwiic
+expander = PCAL6416A()
+
+# Set pin A0 as output
+expander.pinMode(PCAL6416A_A0, OUTPUT)
+
+while True:
+    expander.digitalWrite(PCAL6416A_A0, 1)  # Set HIGH
+    time.sleep(1)
+    expander.digitalWrite(PCAL6416A_A0, 0)  # Set LOW
+    time.sleep(1)

Communication/PCAL6416A/PCAL6416A/Examples/pcal6416a-driveStrength.py

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+# FILE: pcal6416a-driveStrength.py
+# AUTHOR: Fran Fodor @ Soldered
+# BRIEF: Cycle through all four drive-strength levels on pin A0 and set port B to
+#        open-drain mode. Drive strength controls how many output transistor pairs
+#        drive the pin — higher values allow more current to be sourced or sunk.
+# WORKS WITH: PCAL6416A IO Expander breakout: www.solde.red/333351
+# LAST UPDATED: 2026-04-23
+
+import time
+from machine import Pin, I2C
+from pcal6416a import PCAL6416A, PCAL6416A_A0, OUTPUT
+
+# If you aren't using the Qwiic connector, manually enter your I2C pins:
+# i2c = I2C(0, scl=Pin(22), sda=Pin(21))
+# expander = PCAL6416A(i2c)
+
+# Initialize expander over Qwiic
+expander = PCAL6416A()
+
+expander.pinMode(PCAL6416A_A0, OUTPUT)
+
+# Set port B (port 1) to open-drain — pin floats HIGH, pulls LOW when driven low
+expander.openDrainPort(1, True)
+
+expander.digitalWrite(PCAL6416A_A0, 1)  # Hold A0 HIGH throughout
+
+while True:
+    for strength in range(4):
+        # 0 = weakest (fewest transistor pairs), 3 = strongest (most current)
+        expander.driveStrength(PCAL6416A_A0, strength)
+        print("Drive strength set to {}".format(strength))
+        time.sleep(1)

Communication/PCAL6416A/PCAL6416A/Examples/pcal6416a-interrupts.py

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+# FILE: pcal6416a-interrupts.py
+# AUTHOR: Fran Fodor @ Soldered
+# BRIEF: Detect pin-change interrupts from the PCAL6416A using the INT output.
+#        Connect pushbuttons between pins A0/A1 and GND. Connect the INT pin of
+#        the expander to pin D2 on your board.
+# WORKS WITH: PCAL6416A IO Expander breakout: www.solde.red/333351
+# LAST UPDATED: 2026-04-23
+
+from machine import Pin, I2C
+from pcal6416a import PCAL6416A, PCAL6416A_A0, PCAL6416A_A1, INPUT_PULLUP
+
+# If you aren't using the Qwiic connector, manually enter your I2C pins:
+# i2c = I2C(0, scl=Pin(22), sda=Pin(21))
+# expander = PCAL6416A(i2c)
+
+# Initialize expander over Qwiic
+expander = PCAL6416A()
+
+expander.pinMode(PCAL6416A_A0, INPUT_PULLUP)
+expander.pinMode(PCAL6416A_A1, INPUT_PULLUP)
+
+# Enable change-detection interrupt on both pins
+expander.setInterrupt(PCAL6416A_A0, True)
+expander.setInterrupt(PCAL6416A_A1, True)
+
+int_flag = False
+
+
+def isr(pin):
+    global int_flag
+    int_flag = True
+
+
+# D2 on most boards — adjust if needed
+int_pin = Pin(2, Pin.IN, Pin.PULL_UP)
+int_pin.irq(trigger=Pin.IRQ_FALLING, handler=isr)
+
+print("Waiting for interrupts on A0 and A1...")
+
+while True:
+    if int_flag:
+        int_flag = False
+        int_reg = expander.getInterrupts()  # Reading clears the status register
+
+        if int_reg & (1 << PCAL6416A_A0):
+            state = expander.digitalRead(PCAL6416A_A0)
+            print("Interrupt on A0 — pin is now {}".format("HIGH" if state else "LOW"))
+
+        if int_reg & (1 << PCAL6416A_A1):
+            state = expander.digitalRead(PCAL6416A_A1)
+            print("Interrupt on A1 — pin is now {}".format("HIGH" if state else "LOW"))