Merge pull request #7 from ladyada/master

Add interrupt support & examples to MCP23017

Author: ladyada

adafruit_mcp230xx.py

@@ -27,10 +27,9 @@
 
 * Author(s): Tony DiCola
 """
-import digitalio
-
-import adafruit_bus_device.i2c_device as i2c_device
 
+from adafruit_bus_device import i2c_device
+import digitalio
 from micropython import const
 
 
@@ -60,12 +59,11 @@
 _MCP23017_IPOLB         = const(0x03)
 _MCP23017_GPINTENA      = const(0x04)
 _MCP23017_GPINTENB      = const(0x05)
-_MCP23008_DEFVALA       = const(0x06)
-_MCP23008_DEFVALB       = const(0x07)
-_MCP23008_INTCONA       = const(0x08)
-_MCP23008_INTCONB       = const(0x09)
-_MCP23008_IOCONA        = const(0x0A)
-_MCP23008_IOCONB        = const(0x0B)
+_MCP23017_DEFVALA       = const(0x06)
+_MCP23017_DEFVALB       = const(0x07)
+_MCP23017_INTCONA       = const(0x08)
+_MCP23017_INTCONB       = const(0x09)
+_MCP23017_IOCON         = const(0x0A)
 _MCP23017_GPPUA         = const(0x0C)
 _MCP23017_GPPUB         = const(0x0D)
 _MCP23008_INTFA         = const(0x0E)
@@ -267,6 +265,7 @@ def __init__(self, i2c, address=_MCP23017_ADDRESS):
         # Reset to all inputs with no pull-ups and no inverted polarity.
         self.iodir = 0xFFFF
         self.gppu = 0x0000
+        self.iocon = 0x4   # turn on IRQ Pins as open drain
         self._write_u16le(_MCP23017_IPOLA, 0x0000)
 
     def _read_u16le(self, register):
@@ -413,3 +412,62 @@ def get_pin(self, pin):
         """
         assert 0 <= pin <= 15
         return DigitalInOut(pin, self)
+
+    @property
+    def interrupt_configuration(self):
+        """The raw INTCON interrupt control register. The INTCON register
+        controls how the associated pin value is compared for the
+        interrupt-on-change feature. If  a  bit  is  set,  the  corresponding
+        I/O  pin  is  compared against the associated bit in the DEFVAL
+        register. If a bit value is clear, the corresponding I/O pin is
+        compared against the previous value.
+        """
+        return self._read_u16le(_MCP23017_INTCONA)
+
+    @interrupt_configuration.setter
+    def interrupt_configuration(self, val):
+        self._write_u16le(_MCP23017_INTCONA, val)
+
+    @property
+    def interrupt_enable(self):
+        """The raw GPINTEN interrupt control register. The GPINTEN register
+        controls the interrupt-on-change feature for each pin. If a bit is
+        set, the corresponding pin is enabled for interrupt-on-change.
+        The DEFVAL and INTCON registers must also be configured if any pins
+        are enabled for interrupt-on-change.
+        """
+        return self._read_u16le(_MCP23017_GPINTENA)
+
+    @interrupt_enable.setter
+    def interrupt_enable(self, val):
+        self._write_u16le(_MCP23017_GPINTENA, val)
+
+    @property
+    def default_value(self):
+        """The raw DEFVAL interrupt control register. The default comparison
+        value is configured in the DEFVAL register. If enabled (via GPINTEN
+        and INTCON) to compare against the DEFVAL register, an opposite value
+        on the associated pin will cause an interrupt to occur.
+        """
+        return self._read_u16le(_MCP23017_DEFVALA)
+
+    @default_value.setter
+    def default_value(self, val):
+        self._write_u16le(_MCP23017_DEFVALA, val)
+
+
+    @property
+    def io_control(self):
+        """The raw IOCON configuration register. Bit 1 controls interrupt
+        polarity (1 = active-high, 0 = active-low). Bit 2 is whether irq pin
+        is open drain (1 = open drain, 0 = push-pull). Bit 3 is unused.
+        Bit 4 is whether SDA slew rate is enabled (1 = yes). Bit 5 is if I2C
+        address pointer auto-increments (1 = no). Bit 6 is whether interrupt
+        pins are internally connected (1 = yes). Bit 7 is whether registers
+        are all in one bank (1 = no).
+        """
+        return self._read_u8(_MCP23017_IOCON)
+
+    @io_control.setter
+    def io_control(self, val):
+        self._write_u8(_MCP23017_IOCON, val)

examples/mcp230xx_leds_and_buttons.py

@@ -0,0 +1,49 @@
+import board
+import busio
+from digitalio import Direction, Pull
+import adafruit_mcp230xx
+
+# Initialize the I2C bus:
+i2c = busio.I2C(board.SCL, board.SDA)
+
+# Initialize the MCP23017 chip on the bonnet
+mcp = adafruit_mcp230xx.MCP23017(i2c)
+
+# Optionally change the address of the device if you set any of the A0, A1, A2
+# pins.  Specify the new address with a keyword parameter:
+#mcp = adafruit_mcp230xx.MCP23017(i2c, address=0x21)  # MCP23017 w/ A0 set
+
+# Make a list of all the port A pins (a.k.a 0-7)
+port_a_pins = []
+for pin in range(0, 8):
+    port_a_pins.append(mcp.get_pin(pin))
+
+# Make a list of all the port B pins (a.k.a 8-15)
+port_b_pins = []
+for pin in range(8, 16):
+    port_b_pins.append(mcp.get_pin(pin))
+
+# Set all the port A pins to output
+for pin in port_a_pins:
+    pin.direction = Direction.OUTPUT
+
+# Set all the port B pins to input, with pullups!
+for pin in port_b_pins:
+    pin.direction = Direction.INPUT
+    pin.pull = Pull.UP
+
+# Turn on all port A pins for 1/10 of a second
+#while True:
+#    for pin in port_a_pins:
+#        pin.value = True    # turn LED on!
+#        time.sleep(0.1)     # wait 0.1 seconds
+#        pin.value = False   # turn LED off
+
+while True:
+    for num, button in enumerate(port_b_pins):
+        if not button.value:
+            print("Button #", num, "pressed!")
+            # turn on matching port A pin
+            port_a_pins[num].value = True    # turn LED on!
+        else:
+            port_a_pins[num].value = False    # turn LED off

examples/mcp230xx_leds_and_buttons_irq.py

@@ -0,0 +1,58 @@
+import board
+import busio
+from digitalio import DigitalInOut, Direction, Pull
+import adafruit_mcp230xx
+
+# Initialize the I2C bus:
+i2c = busio.I2C(board.SCL, board.SDA)
+
+# Initialize the MCP23017 chip on the bonnet
+mcp = adafruit_mcp230xx.MCP23017(i2c)
+
+# Optionally change the address of the device if you set any of the A0, A1, A2
+# pins.  Specify the new address with a keyword parameter:
+#mcp = adafruit_mcp230xx.MCP23017(i2c, address=0x21)  # MCP23017 w/ A0 set
+
+# Make a list of all the port A pins (a.k.a 0-7)
+port_a_pins = []
+for pin in range(0, 8):
+    port_a_pins.append(mcp.get_pin(pin))
+
+# Make a list of all the port B pins (a.k.a 8-15)
+port_b_pins = []
+for pin in range(8, 16):
+    port_b_pins.append(mcp.get_pin(pin))
+
+# Set all the port A pins to output
+for pin in port_a_pins:
+    pin.direction = Direction.OUTPUT
+
+# Set all the port B pins to input, with pullups!
+for pin in port_b_pins:
+    pin.direction = Direction.INPUT
+    pin.pull = Pull.UP
+
+# Set up to check all the port B pins (pins 8-15) w/interrupts!
+mcp.interrupt_enable = 0xFF00        # INTerrupt ENable top 8 bits
+# If intcon is set to 0's we will get interrupts on
+# both button presses and button releases
+mcp.interrupt_configuration = 0x0000         # interrupt on any change
+
+# Or, we can ask to be notified CONTINUOUSLY if a pin goes LOW (button press)
+# we won't get an IRQ pulse when the pin is HIGH!
+#mcp.interrupt_configuration = 0xFF00         # notify pin value
+#mcp.default_value = 0xFF00         # default value is 'high' so notify whenever 'low'
+
+# connect the IRQ B pin to D4
+irq_b = DigitalInOut(board.D4)
+
+while True:
+    if not irq_b.value:
+        print("IRQ B went off")
+        for num, button in enumerate(port_b_pins):
+            if not button.value:
+                print("Button #", num, "pressed!")
+                # turn on matching port A pin
+                port_a_pins[num].value = True    # turn LED on!
+            else:
+                port_a_pins[num].value = False    # turn LED off