import digitalio def intify_coordinate(row, col): return row << 8 | col class DiodeOrientation: ''' Orientation of diodes on handwired boards. You can think of: COLUMNS = vertical ROWS = horizontal ''' COLUMNS = 0 ROWS = 1 class MatrixScanner: def __init__( self, cols, rows, diode_orientation=DiodeOrientation.COLUMNS, rollover_cols_every_rows=None, ): self.len_cols = len(cols) self.len_rows = len(rows) # A pin cannot be both a row and column, detect this by combining the # two tuples into a set and validating that the length did not drop # # repr() hackery is because CircuitPython Pin objects are not hashable unique_pins = {repr(c) for c in cols} | {repr(r) for r in rows} assert ( len(unique_pins) == self.len_cols + self.len_rows ), 'Cannot use a pin as both a column and row' del unique_pins self.diode_orientation = diode_orientation # __class__.__name__ is used instead of isinstance as the MCP230xx lib # does not use the digitalio.DigitalInOut, but rather a self defined one: # https://github.com/adafruit/Adafruit_CircuitPython_MCP230xx/blob/3f04abbd65ba5fa938fcb04b99e92ae48a8c9406/adafruit_mcp230xx/digital_inout.py#L33 if self.diode_orientation == DiodeOrientation.COLUMNS: self.outputs = [ x if x.__class__.__name__ is 'DigitalInOut' else digitalio.DigitalInOut(x) for x in cols ] self.inputs = [ x if x.__class__.__name__ is 'DigitalInOut' else digitalio.DigitalInOut(x) for x in rows ] self.translate_coords = True elif self.diode_orientation == DiodeOrientation.ROWS: self.outputs = [ x if x.__class__.__name__ is 'DigitalInOut' else digitalio.DigitalInOut(x) for x in rows ] self.inputs = [ x if x.__class__.__name__ is 'DigitalInOut' else digitalio.DigitalInOut(x) for x in cols ] self.translate_coords = False else: raise ValueError( 'Invalid DiodeOrientation: {}'.format(self.diode_orientation) ) for pin in self.outputs: pin.switch_to_output() for pin in self.inputs: pin.switch_to_input(pull=digitalio.Pull.UP) self.rollover_cols_every_rows = rollover_cols_every_rows if self.rollover_cols_every_rows is None: self.rollover_cols_every_rows = self.len_rows self.len_state_arrays = self.len_cols * self.len_rows self.state = bytearray(self.len_state_arrays) self.report = bytearray(3) def scan_for_changes(self): ''' Poll the matrix for changes and return either None (if nothing updated) or a bytearray (reused in later runs so copy this if you need the raw array itself for some crazy reason) consisting of (row, col, pressed) which are (int, int, bool) ''' ba_idx = 0 any_changed = False for oidx, opin in enumerate(self.outputs): opin.value = False for iidx, ipin in enumerate(self.inputs): # cast to int to avoid # # >>> xyz = bytearray(3) # >>> xyz[2] = True # Traceback (most recent call last): # File "", line 1, in # OverflowError: value would overflow a 1 byte buffer # # I haven't dived too far into what causes this, but it's # almost certainly because bool types in Python aren't just # aliases to int values, but are proper pseudo-types new_val = int(not ipin.value) old_val = self.state[ba_idx] if old_val != new_val: if self.translate_coords: new_oidx = oidx + self.len_cols * ( iidx // self.rollover_cols_every_rows ) new_iidx = iidx - self.rollover_cols_every_rows * ( iidx // self.rollover_cols_every_rows ) self.report[0] = new_iidx self.report[1] = new_oidx else: self.report[0] = oidx self.report[1] = iidx self.report[2] = new_val self.state[ba_idx] = new_val any_changed = True break ba_idx += 1 opin.value = True if any_changed: break if any_changed: return self.report