86 lines
2.2 KiB
Python
86 lines
2.2 KiB
Python
"""Send this code, run and watch the repl.
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Then turn the wheel slowly to see the change"""
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import board
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import rp2pio
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import adafruit_pioasm
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import array
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program = """
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; use the osr for count
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; input pins c1 c2
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set y, 0 ; clear y
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mov osr, y ; and clear osr
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read:
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; x will be the old value
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; y the new values
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mov x, y ; store old Y in x
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in null, 32 ; Clear ISR - using y
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in pins, 2 ; read two pins into y
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mov y, isr
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jmp x!=y, different ; Jump if its different
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jmp read ; otherwise loop back to read
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different:
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; x has old value, y has new.
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; extract the upper bit of X.
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in x, 31 ; get bit 31 - old p1 (remember which direction it came in)
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in null, 31 ; keep only 1 bit
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mov x, isr ; put this back in x
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jmp !x, c1_old_zero
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c1_old_not_zero:
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jmp pin, count_up
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jmp count_down
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c1_old_zero:
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jmp pin, count_down
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; fall through
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count_up:
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; for a clockwise move - we'll add 1 by inverting
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mov x, ~ osr ; store inverted OSR on x
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jmp x--, fake ; use jump to take off 1
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fake:
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mov x, ~ x ; invert back
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jmp send
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count_down:
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; for a clockwise move, just take one off
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mov x, osr ; store osr in x
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jmp x--, send ; dec and send
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send:
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; send x.
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mov isr, x ; send it
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push noblock ; put ISR into input FIFO
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mov osr, x ; put X back in OSR
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jmp read ; loop back
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"""
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assembled = adafruit_pioasm.assemble(program)
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## set up a statemachine
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left_enc = rp2pio.StateMachine(
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assembled, frequency=0, first_in_pin=board.GP20, jmp_pin=board.GP21, in_pin_count=2
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)
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right_enc = rp2pio.StateMachine(
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assembled, frequency=0, first_in_pin=board.GP26, jmp_pin=board.GP27, in_pin_count=2
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)
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buffer = array.array("i", [0])
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left_data = 0
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right_data = 0
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while True:
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# read data from the fifo
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if left_enc.in_waiting:
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left_enc.readinto(buffer)
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left_data = buffer[0]
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# print it.
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print(left_data, right_data)
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if right_enc.in_waiting:
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right_enc.readinto(buffer)
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right_data = buffer[0]
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# print it.
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print(left_data, right_data)
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