109 lines
3.8 KiB
Python
109 lines
3.8 KiB
Python
import digitalio
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from kmk.consts import DiodeOrientation
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class MatrixScanner:
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def __init__(
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self, cols, rows,
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diode_orientation=DiodeOrientation.COLUMNS,
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rollover_cols_every_rows=None,
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):
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# A pin cannot be both a row and column, detect this by combining the
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# two tuples into a set and validating that the length did not drop
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#
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# repr() hackery is because CircuitPython Pin objects are not hashable
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unique_pins = {repr(c) for c in cols} | {repr(r) for r in rows}
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if len(unique_pins) != len(cols) + len(rows):
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raise ValueError('Cannot use a pin as both a column and row')
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self.cols = cols
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self.rows = rows
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self.len_cols = len(cols)
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self.len_rows = len(rows)
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self.diode_orientation = diode_orientation
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if self.diode_orientation == DiodeOrientation.COLUMNS:
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self.outputs = self.cols
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self.inputs = self.rows
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self.translate_coords = True
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elif self.diode_orientation == DiodeOrientation.ROWS:
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self.outputs = self.rows
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self.inputs = self.cols
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self.translate_coords = False
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else:
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raise ValueError('Invalid DiodeOrientation: {}'.format(
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self.diode_orientation,
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))
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for pin in self.outputs:
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pin.switch_to_output()
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for pin in self.inputs:
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pin.switch_to_input(pull=digitalio.Pull.DOWN)
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self.rollover_cols_every_rows = rollover_cols_every_rows
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if self.rollover_cols_every_rows is None:
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self.rollover_cols_every_rows = self.len_rows
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self.len_state_arrays = self.len_cols * self.len_rows
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self.state = bytearray(self.len_state_arrays)
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self.report = bytearray(3)
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def scan_for_changes(self):
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'''
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Poll the matrix for changes and return either None (if nothing updated)
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or a bytearray (reused in later runs so copy this if you need the raw
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array itself for some crazy reason) consisting of (row, col, pressed)
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which are (int, int, bool)
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'''
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ba_idx = 0
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any_changed = False
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for oidx, opin in enumerate(self.outputs):
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opin.value(True)
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for iidx, ipin in enumerate(self.inputs):
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# cast to int to avoid
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#
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# >>> xyz = bytearray(3)
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# >>> xyz[2] = True
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# Traceback (most recent call last):
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# File "<stdin>", line 1, in <module>
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# OverflowError: value would overflow a 1 byte buffer
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#
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# I haven't dived too far into what causes this, but it's
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# almost certainly because bool types in Python aren't just
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# aliases to int values, but are proper pseudo-types
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new_val = int(ipin.value())
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old_val = self.state[ba_idx]
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if old_val != new_val:
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if self.translate_coords:
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new_oidx = oidx + self.len_cols * (iidx // self.rollover_cols_every_rows)
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new_iidx = iidx - self.rollover_cols_every_rows * (
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iidx // self.rollover_cols_every_rows
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)
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self.report[0] = new_iidx
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self.report[1] = new_oidx
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else:
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self.report[0] = oidx
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self.report[1] = iidx
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self.report[2] = new_val
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self.state[ba_idx] = new_val
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any_changed = True
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break
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ba_idx += 1
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opin.value(False)
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if any_changed:
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break
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if any_changed:
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return self.report
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