Merge pull request #14 from jardiamj/improve_interrupt

Improve interrupt

Author: makermelissa

adafruit_mcp230xx/mcp23017.py

@@ -49,6 +49,10 @@
 _MCP23017_GPPUB         = const(0x0D)
 _MCP23017_GPIOA         = const(0x12)
 _MCP23017_GPIOB         = const(0x13)
+_MCP23017_INTFA         = const(0x0E)
+_MCP23017_INTFB         = const(0x0F)
+_MCP23017_INTCAPA       = const(0x10)
+_MCP23017_INTCAPB       = const(0x11)
 
 
 class MCP23017(MCP230XX):
@@ -218,7 +222,6 @@ def default_value(self):
     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
@@ -234,3 +237,43 @@ def io_control(self):
     @io_control.setter
     def io_control(self, val):
         self._write_u8(_MCP23017_IOCON, val)
+
+    @property
+    def int_flag(self):
+        """Returns a list with the pin numbers that caused an interrupt
+        port A ----> pins 0-7
+        port B ----> pins 8-15
+        """
+        intf = self._read_u16le(_MCP23017_INTFA)
+        flags = [pin for pin in range(16) if intf & (1 << pin)]
+        return flags
+
+    @property
+    def int_flaga(self):
+        """Returns a list of pin numbers that caused an interrupt in port A
+        pins: 0-7
+        """
+        intfa = self._read_u8(_MCP23017_INTFA)
+        flags = [pin for pin in range(8) if intfa & (1 << pin)]
+        return flags
+
+    @property
+    def int_flagb(self):
+        """Returns a list of pin numbers that caused an interrupt in port B
+        pins: 8-15
+        """
+        intfb = self._read_u8(_MCP23017_INTFB)
+        flags = [pin+8 for pin in range(8) if intfb & (1 << pin)]
+        return flags
+
+    def clear_ints(self):
+        """Clears interrupts by reading INTCAP."""
+        self._read_u16le(_MCP23017_INTCAPA)
+
+    def clear_inta(self):
+        """Clears port A interrupts."""
+        self._read_u8(_MCP23017_INTCAPA)
+
+    def clear_intb(self):
+        """Clears port B interrupts."""
+        self._read_u8(_MCP23017_INTCAPB)

examples/mcp230xx_event_detect_interrupt.py

@@ -0,0 +1,69 @@
+from time import sleep
+
+import board
+import busio
+from digitalio import Direction, Pull
+from RPi import GPIO
+from adafruit_mcp230xx.mcp23017 import MCP23017
+
+# Initialize the I2C bus:
+i2c = busio.I2C(board.SCL, board.SDA)
+
+# Initialize the MCP23017 chip on the bonnet
+mcp = 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 = MCP23017(i2c, address=0x21)  # MCP23017 w/ A0 set
+
+# Make a list of all the pins (a.k.a 0-16)
+pins = []
+for pin in range(0, 16):
+    pins.append(mcp.get_pin(pin))
+
+# Set all the pins to input
+for pin in 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 = 0xFFFF        # Enable Interrupts in all pins
+# 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
+mcp.io_control = 0x44   # Interrupt as open drain and mirrored
+mcp.clear_ints()        # Interrupts need to be cleared initially
+
+# 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 = 0xFFFF         # notify pin value
+#mcp.default_value = 0xFFFF         # default value is 'high' so notify whenever 'low'
+
+def print_interrupt(port):
+    '''Callback function to be called when an Interrupt occurs.'''
+    for pin_flag in mcp.int_flag:
+        print("Interrupt connected to Pin: {}".format(port))
+        print("Pin number: {} changed to: {}".format(pin_flag, pins[pin_flag].value))
+    mcp.clear_ints()
+
+# connect either interrupt pin to the Raspberry pi's pin 17.
+# They were previously configured as mirrored.
+GPIO.setmode(GPIO.BCM)
+interrupt = 17
+GPIO.setup(interrupt, GPIO.IN, GPIO.PUD_UP) # Set up Pi's pin as input, pull up
+
+# The add_event_detect fuction will call our print_interrupt callback function
+# every time an interrupt gets triggered.
+GPIO.add_event_detect(interrupt, GPIO.FALLING, callback=print_interrupt, bouncetime=10)
+
+# The following lines are so the program runs for at least 60 seconds,
+# during that time it will detect any pin interrupt and print out the pin number
+# that changed state and its current state.
+# The program can be terminated using Ctrl+C. It doesn't matter how it
+# terminates it will always run GPIO.cleanup().
+try:
+    print("When button is pressed you'll see a message")
+    sleep(60) # You could run your main while loop here.
+    print("Time's up. Finished!")
+finally:
+    GPIO.cleanup()