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 call_mapped_input_functions(input_func_map):
for board_i in range(MAX_BOARDS):
this_board_ifm = [m for m in input_func_map if m['board'] == board_i]
# read the interupt status of this PiFace board
int_bit = pfcom.read(pfcom.INTFB, board_i)
if int_bit == 0:
continue # The interupt has not been flagged on this board
int_bit_num = pfcom.get_bit_num(int_bit)
int_byte = pfcom.read(pfcom.INTCAPB, board_i)
into = (int_bit & int_byte) >> int_bit_num # bit changed into (0/1)
# for each mapping (on this board) see if we have a callback
for mapping in this_board_ifm:
if int_bit_num == mapping['index'] and \
(mapping['into'] is None or into == mapping['into']):
mapping['callback'](int_bit, int_byte)
return # one at a time
def _call_mapped_input_functions(input_func_map):
"""Finds which board caused the interrupt and calls the mapped
function.
Returns whether the wait_for_input function should keep waiting for input
"""
for board_i in range(MAX_BOARDS):
this_board_ifm = [m for m in input_func_map if m['board'] == board_i]
# read the interrupt status of this PiFace board
# interrupt bit (int_bit) - bit map showing what caused the interrupt
int_bit = pfcom.read(pfcom.INTFB, board_i)
if int_bit == 0:
continue # The interrupt has not been flagged on this board
int_bit_num = pfcom.get_bit_num(int_bit)
# interrupt byte (int_byte) - snapshot of in port when int occured
int_byte = pfcom.read(pfcom.INTCAPB, board_i)
# direction - whether the bit changed into a 1 or a 0
direction = (int_bit & int_byte) >> int_bit_num
# for each mapping (on this board) see if we have a callback
for mapping in this_board_ifm:
if int_bit_num == mapping['index'] and \
(mapping['direction'] is None or
direction == mapping['direction']):
# run the callback
keep_waiting = mapping['callback'](int_bit, int_byte)
# stop waiting for interrupts, by default
if keep_waiting is None:
keep_waiting = False
return keep_waiting
# This event does not have a mapped function, keep waiting
return True
def clear_interrupts():
"""Clears the interrupt flags by 'pfcom.read'ing the capture register
on all boards
"""
for i in range(MAX_BOARDS):
pfcom.read(pfcom.INTCAPB, i)
