##### DMA EXAMPLE #####

import time
from machine import Pin
import rp2
import array
import uctypes

##### CONFIGURATION DATA #####

LED_PIN = 25

DMA_BASE = 0x50000000   # Physical location of the DMA in memory
PIO0_SM0_TX = 0x50200010 # PIO0, State Machine 0 TX-Fifo

##### PIO PROGRAMS #####

@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW)
def blink_loop():
    """
    Continuously input pairs of data: Light on pause length, light off pause length.  
    """
    wrap_target()
    #### Get Data 1 ######################################################### 
    pull(block)                     # Pull "on" count from TX-FIFO
    mov(x, osr)                     # Store count 
    #### LED ON #############################################################
    set(pins, 1)                    # Flip the LED pin ON
    label("on_loop")                # Loop X number times
    jmp(x_dec, "on_loop")  [6]      # Count 7 cycles for each loop (jmp + 6)
    #### Get Data 2 #########################################################
    pull(block)                     # Pull "off" count from TX-FIFO
    mov(x, osr)                     # Store count
    #### LED OFF ############################################################
    set(pins, 0)                    # Flip the LED pin OFF
    label("off_loop")               # Loop X number times
    jmp(x_dec, "off_loop")  [6]     # Count 7 cycles for each loop (jmp + 6)
    #### LOOP ENDS ########################################################## 
    wrap()                          # Off cycle complete; return to loop


##### Initialization #####

# Prepare DMA Data 
blink_data = array.array('L', [6000000,3000000])
blink_data_addr = uctypes.addressof(blink_data)
# Allocate DMA channel
dma_blink_data = rp2.DMA()
# Pack our Control Word
dma_blink_data_ctrl = dma_blink_data.pack_ctrl(
    treq_sel=0,                  # DREQ for PIO0, SM0
    inc_read=True,               # Increment read address each time you send
    inc_write=False,             # Write address stays the same (the Pio TX-FIFO)
    size=2,                      # 4-byte transfers
    enable=True)

# Attach communication pins
LED_output_pin = Pin(LED_PIN, Pin.OUT)

# Set up the state machines
sm_blinker = rp2.StateMachine(0, blink_loop, freq=150000000, set_base=LED_output_pin)

##### MAIN PROGRAM #####

print ("Begin Test!")
sm_blinker.active(1)
print (f"  Blinker FIFO before DMA: {sm_blinker.tx_fifo()}")

# Begin data transfer:
dma_blink_data.config(
    read=blink_data_addr,     # Our data address
    write=sm_blinker,         # State machine object. This should go to the TX-FIFO.
    count=2,                  # Two chunks of data
    ctrl=dma_blink_data_ctrl, # Control word configured above
    trigger=True)             # Start immediately

print (f"  Blinker FIFO After DMA: {sm_blinker.tx_fifo()}")

time.sleep(2)

print ("Manually placing data:")
sm_blinker.put(6000000)
sm_blinker.put(3000000)
print (f"  Blinker FIFO After Manual Put(): {sm_blinker.tx_fifo()}")

time.sleep(10)

sm_blinker.active(0)
print ("Test Complete.")