# SPDX-FileCopyrightText: 2022 Jamon Terrell <[email protected]>
# SPDX-License-Identifier: MIT

from rp2 import PIO, StateMachine, asm_pio
from machine import Pin
import utime
@asm_pio(autopush=True, push_thresh=32)
def encoder():
    label("start")
    wait(0, pin, 0)         # Wait for CLK to go low
    jmp(pin, "WAIT_HIGH")   # if Data is low
    mov(x, invert(x))           # Increment X
    jmp(x_dec, "nop1")
    label("nop1")
    mov(x, invert(x))
    label("WAIT_HIGH")      # else
    jmp(x_dec, "nop2")          # Decrement X
    label("nop2")
    
    wait(1, pin, 0)         # Wait for CLK to go high
    jmp(pin, "WAIT_LOW")    # if Data is low
    jmp(x_dec, "nop3")          # Decrement X
    label("nop3")
    
    label("WAIT_LOW")       # else
    mov(x, invert(x))           # Increment X
    jmp(x_dec, "nop4")
    label("nop4")
    mov(x, invert(x))
    wrap()

    
sm1 = StateMachine(1, encoder, freq=125_000_000, in_base=Pin(3), jmp_pin=Pin(2))
sm1.active(1)

while(True):
    utime.sleep(1)
    sm1.exec("in_(x, 32)")
    x = sm1.get()
    print(x)