Documentation for setting a callback

[bretfrederick]

Hello, I'm fairly new to uPython. I'm using this library for my ESP-32 and MCP23017 expander. Can you provide an example of using INTA/B for callback functions?

[bretfrederick]

Answered my own question. For anyone else trying to figure out how to use the interrupt from MCP23017, here's what works for me. I'm using the ESP-32 DevKit v4 with the Expand 2 Click MCP23017 breakout

from machine import I2C, Pin
sda_pin=Pin(21)
scl_pin=Pin(22)
i2c=I2C(sda=sda_pin, scl=scl_pin)
mcp=mcp23017.MCP23017(i2c)

# this is the ESP-32 pin to get the interrupt on
int_pin=Pin(12, Pin.IN)

# callback function responding to MCP pin
mcp_cbk=lambda x : print("MCP pin interrupt")
int_pin.irq(trigger=Pin.IRQ_FALLING, handler=mcp_cbk)

# Do something here to change the state of MCP pin on port A (I have buttons) 
# get the MCP pin that triggered the interrupt
mcp.interrupt_triggered_gpio(port=0)

# reset the MCP register to capture the next trigger
mcp.interrupt_captured_gpio(port=0)

This is working for me. Maybe there's a better method of getting the interrupts from MCP23017 using this library? For now it's working great. Thanks for the useful library.

[mcauser]

That is correct. Here's how you do it using the property interface:

from machine import I2C, Pin
sda_pin=Pin(21)
scl_pin=Pin(22)
i2c=I2C(sda=sda_pin, scl=scl_pin)
mcp=mcp23017.MCP23017(i2c)

# this is the ESP-32 pin to get the interrupt on
int_pin=Pin(12, Pin.IN)

# callback function responding to MCP pin
mcp_cbk=lambda x : print("MCP pin interrupt")
int_pin.irq(trigger=Pin.IRQ_FALLING, handler=mcp_cbk)

# configure the first 4 pins as input (1=in, 0=out)
mcp.porta.mode = 0b00001111

# enable pull ups on the first 4 pins (0=disabled, 1=enabled)
mcp.porta.pullup = 0b00001111

# enable interrupts on the first 4 pins (0=disabled, 1=enabled)
mcp.porta.interrupt_enable = 0b00001111

# Do something here to change the state of MCP pin on port A
# eg. connect pin 0 to GND with a push button or wire.

# get the MCP pin that triggered the interrupt - after reading this register, interrupts will fire again on the next pin state change.
print(mcp.porta.interrupt_flag)

# reset the MCP register to capture the next trigger
print(mcp.porta.interrupt_captured)