from time import sleep
import pigpio

DIR = 20     # Direction GPIO Pin
STEP = 21    # Step GPIO Pin
SWITCH = 16  # GPIO pin of switch

# Connect to pigpiod daemon
pi = pigpio.pi()

# Set up pins as an output
pi.set_mode(DIR, pigpio.OUTPUT)
pi.set_mode(STEP, pigpio.OUTPUT)

# Set up input switch
pi.set_mode(SWITCH, pigpio.INPUT)
pi.set_pull_up_down(SWITCH, pigpio.PUD_UP)

MODE = (14, 15, 18)   # Microstep Resolution GPIO Pins
RESOLUTION = {'Full': (0, 0, 0),
              'Half': (1, 0, 0),
              '1/4': (0, 1, 0),
              '1/8': (1, 1, 0),
              '1/16': (0, 0, 1),
              '1/32': (1, 0, 1)}
for i in range(3):
    pi.write(MODE[i], RESOLUTION['Full'][i])


def generate_ramp(ramp):
    """Generate ramp wave forms.

    ramp:  List of [Frequency, Steps]
    """
    pi.wave_clear()     # clear existing waves
    length = len(ramp)  # number of ramp levels
    wid = [-1] * length

    # Generate a wave per ramp level
    for i in range(length):
        frequency = ramp[i][0]
        micros = int(500000 / frequency)
        wf = []
        wf.append(pigpio.pulse(1 << STEP, 0, micros))  # pulse on
        wf.append(pigpio.pulse(0, 1 << STEP, micros))  # pulse off
        pi.wave_add_generic(wf)
        wid[i] = pi.wave_create()

    # Generate a chain of waves
    chain = []
    for i in range(length):
        steps = ramp[i][1]
        x = steps & 255
        y = steps >> 8
        chain += [255, 0, wid[i], 255, 1, x, y]

    pi.wave_chain(chain)  # Transmit chain.


try:
    old_ramp = 0
    while True:
        new_ramp = pi.read(SWITCH)  # Read switch
        if new_ramp != old_ramp:
            if new_ramp:
                # Ramp up
                generate_ramp([[320, 200],
                               [500, 400],
                               [800, 500],
                               [1000, 700],
                               [1600, 900],
                               [2000, 10000]])
            else:
                # Ramp down
                generate_ramp([[1600, 900],
                               [1000, 700],
                               [500, 500],
                               [320, 400]])

            old_ramp = new_ramp
        sleep(.1)

except KeyboardInterrupt:
    print ("\nCtrl-C pressed.  Stopping PIGPIO and exiting...")
finally:
    pi.wave_clear()
    pi.stop()