fix to make buttons and leds compatible with pca10056

[jpconstantineau]

Minor updates to make code for buttons and LEDs running on the PCA10056 compatible with the PCA10100. Focus was to make this code snippet portable between the two boards (They are practically identical...):

import board
from digitalio import DigitalInOut, Direction, Pull
import time

# LED setup.

led1 = DigitalInOut(board.LED1)
led2 = DigitalInOut(board.LED2)
led3 = DigitalInOut(board.LED3)
led4 = DigitalInOut(board.LED4)
led1.direction = Direction.OUTPUT
led2.direction = Direction.OUTPUT
led3.direction = Direction.OUTPUT
led4.direction = Direction.OUTPUT

# Button setup.

button1 = DigitalInOut(board.BUTTON1)
button2 = DigitalInOut(board.BUTTON2)
button3 = DigitalInOut(board.BUTTON3)
button4 = DigitalInOut(board.BUTTON4)

button1.pull = Pull.UP
button2.pull = Pull.UP
button3.pull = Pull.UP
button4.pull = Pull.UP

while True:
    led1.value = button1.value
    led2.value = button2.value
    led3.value = button3.value
    led4.value = button4.value

    time.sleep(0.1)

changes:

• Remove conflicting LED usage as these should be left for user (just like the pca10056)
• Add button definition for Button1 and button2 to be identical to pca10056.

Notes
Did not remove redundant "Default" definitions for backward compatibility
Did not update data pins definitions to match the structure of the PCA10056.

[tannewt]

One suggestion. Otherwise good. Thanks!

[dhalbert]

requested change done -- thanks!

addressed