def init(init_board=True):
"""Initialises the PiFace Digital board"""
pfcom.init(SPI_BUS, SPI_CHIP_SELECT)
if init_board:
# set up each board
ioconfig = pfcom.BANK_OFF | \
pfcom.INT_MIRROR_OFF | pfcom.SEQOP_ON | pfcom.DISSLW_OFF | \
pfcom.HAEN_ON | pfcom.ODR_OFF | pfcom.INTPOL_LOW
pfd_detected = False
for board_index in range(MAX_BOARDS):
pfcom.write(ioconfig, pfcom.IOCON, board_index) # configure
if not pfd_detected:
if pfcom.read(pfcom.IOCON, board_index) == ioconfig:
pfd_detected = True
pfcom.write(0, pfcom.GPIOA, board_index) # clear port A
pfcom.write(0, pfcom.IODIRA, board_index) # set port A as outputs
pfcom.write(0xff, pfcom.IODIRB, board_index) # set port B as inputs
pfcom.write(0xff, pfcom.GPPUB, board_index) # set port B pullups on
if not pfd_detected:
raise NoPiFaceDigitalDetectedError(
"There was no PiFace Digital board detected!"
)
def disable_interrupts():
# neither edge
with open(GPIO_INTERRUPT_DEVICE_EDGE, 'w') as gpio25edge:
gpio25edge.write('none')
# remove the pin from userspace
with open(GPIO_UNEXPORT_FILE, 'w') as unexport_file:
unexport_file.write(str(GPIO_INTERRUPT_PIN))
# disable the interrupt
for board_index in range(MAX_BOARDS):
pfcom.write(0, pfcom.GPINTENB, board_index)
def disable_interupts():
with open(GPIO_INTERUPT_DEVICE+'edge', 'w') as gpio25edge:
gpio25edge.write('none')
try:
subprocess.check_call(["gpio-admin", "unexport", "25"])
except subprocess.CalledProcessError as e:
if e.returncode != 4: # we can ignore 4 (gpio25 is already down)
raise e
for board_index in range(MAX_BOARDS):
pfcom.write(0, pfcom.GPINTENB, board_index) # disable the interupt
def enable_interrupts():
# enable interrupts
for board_index in range(MAX_BOARDS):
pfcom.write(0xff, pfcom.GPINTENB, board_index)
try:
_bring_gpio_interrupt_into_userspace()
_set_gpio_interrupt_edge()
except Timeout as e:
raise InterruptEnableException(
"There was an error bringing gpio%d into userspace. %s" % \
(GPIO_INTERRUPT_PIN, e.message)
)
def enable_interupts():
for board_index in range(MAX_BOARDS):
pfcom.write(0xff, pfcom.GPINTENB, board_index)
# access quick2wire-gpio-admin for gpio pin twiddling
try:
subprocess.check_call(["gpio-admin", "export", "25"])
except subprocess.CalledProcessError as e:
if e.returncode != 4: # we can ignore 4 (gpio25 is already up)
raise e
# we're only interested in the falling edges of this file (1 -> 0)
with open(GPIO_INTERUPT_DEVICE+'edge', 'w') as gpio25edge:
gpio25edge.write('falling')