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47 lines
1.2 KiB
47 lines
1.2 KiB
4 years ago
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# Example using PIO to wait for a pin change and raise an IRQ.
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#
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# Demonstrates:
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# - PIO wrapping
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# - PIO wait instruction, waiting on an input pin
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# - PIO irq instruction, in blocking mode with relative IRQ number
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# - setting the in_base pin for a StateMachine
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# - setting an irq handler for a StateMachine
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# - instantiating 2x StateMachine's with the same program and different pins
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import time
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from machine import Pin
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import rp2
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@rp2.asm_pio()
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def wait_pin_low():
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wrap_target()
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wait(0, pin, 0)
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irq(block, rel(0))
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wait(1, pin, 0)
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wrap()
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def handler(sm):
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# Print a (wrapping) timestamp, and the state machine object.
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print(time.ticks_ms(), sm)
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# Instantiate StateMachine(0) with wait_pin_low program on Pin(16).
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pin16 = Pin(16, Pin.IN, Pin.PULL_UP)
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sm0 = rp2.StateMachine(0, wait_pin_low, in_base=pin16)
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sm0.irq(handler)
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# Instantiate StateMachine(1) with wait_pin_low program on Pin(17).
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pin17 = Pin(17, Pin.IN, Pin.PULL_UP)
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sm1 = rp2.StateMachine(1, wait_pin_low, in_base=pin17)
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sm1.irq(handler)
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# Start the StateMachine's running.
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sm0.active(1)
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sm1.active(1)
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# Now, when Pin(16) or Pin(17) is pulled low a message will be printed to the REPL.
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