158 lines
4.9 KiB
Python
158 lines
4.9 KiB
Python
# (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
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# and is covered by GPLv3 license found in COPYING.
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#
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# mempad.py - Numeric keypad implemented with membrane metal-dome, not touch.
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#
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import array, utime, pyb
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from uasyncio.queues import Queue
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from machine import Pin
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from random import shuffle
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from numpad import NumpadBase
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NUM_ROWS = const(4)
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NUM_COLS = const(3)
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SAMPLE_RATE = const(5) # ms
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NUM_SAMPLES = const(10) # this many matching samples required for debounce
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class MembraneNumpad(NumpadBase):
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# (row, col) => keycode
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DECODER = 'y0x987654321'
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def __init__(self, loop):
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super(MembraneNumpad, self).__init__(loop)
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# we can handle faster key-repeat start
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self.repeat_delay = 250
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# No idea how to pick a safe timer number.
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self.timer = pyb.Timer(7)
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self.cols = [Pin(i, Pin.IN, pull=Pin.PULL_UP)
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for i in ('M2_COL0', 'M2_COL1', 'M2_COL2')]
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self.rows = [Pin(i, Pin.OUT_OD, value=0)
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for i in ('M2_ROW0', 'M2_ROW1', 'M2_ROW2', 'M2_ROW3')]
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self.scan_order = array.array('b', list(range(NUM_ROWS)))
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self.history = bytearray(NUM_ROWS * NUM_COLS)
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# We scan in random order, because Tempest.
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# - scanning only starts when something pressed
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# - complete scan is done before acting on what was measured
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shuffle(self.scan_order)
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self.scan_count = 0
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self.waiting_for_any = True
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for c in self.cols:
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c.irq(self.anypress_irq, Pin.IRQ_FALLING|Pin.IRQ_RISING)
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# ready to start
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self.loop = loop
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def anypress_irq(self, pin):
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# come here for any change, high or low
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if self.waiting_for_any:
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# something was pressed, but we don't know what.. start a scan+debounce
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self._start_scan()
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def start(self):
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# Begin scanning for events
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self._disabled = False
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self._wait_any()
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def _wait_any(self):
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# wait for any press.
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self.timer.deinit()
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for r in self.rows:
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r.off()
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self.waiting_for_any = True
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def _start_scan(self):
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# reset and start a new scan
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if self._disabled: return
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self.waiting_for_any = False
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#assert self.scan_count == 0 # can happen when CPU busy?
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self.scan_count = NUM_SAMPLES-1
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self.history = bytearray(NUM_ROWS * NUM_COLS)
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self.timer.init(freq=1000//SAMPLE_RATE, callback=self._measure_irq)
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self.loop.call_later_ms(SAMPLE_RATE * (NUM_SAMPLES + 2), self._finish_scan)
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def _measure_irq(self, _timer):
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# CHALLENGE: Called at high rate, and cannot do memory alloc.
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# - sample all keys once, record any that are pressed
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if self.scan_count == NUM_SAMPLES:
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# First irq may be a runt of unknown length, so don't collect data
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# until after first time called.
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pass
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else:
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for i in range(NUM_ROWS):
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row = self.scan_order[i]
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self.rows[0].value(row != 0)
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self.rows[1].value(row != 1)
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self.rows[2].value(row != 2)
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self.rows[3].value(row != 3)
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# sample the column values
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if self.cols[0].value() == 0:
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col = 0
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elif self.cols[1].value() == 0:
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col = 1
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elif self.cols[2].value() == 0:
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col = 2
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else:
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continue
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# track any press observed
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self.history[(row * NUM_COLS) + col] += 1
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# should we do that again in a bit?
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if self.scan_count == 0:
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# we are done a full scan
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_timer.deinit()
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else:
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self.scan_count -= 1
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def _finish_scan(self):
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# we're done a full scan (mulitple times: NUM_SAMPLES)
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# - not trying to support multiple presses, just one
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from main import dis
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from display import FontTiny
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if self.scan_count != 0:
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# This happened like once, some kind of race/timing window. Recover.
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self._start_scan()
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return
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if sum(self.history) == 0:
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# all keys are 100% up.
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self._key_event('')
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# stop scanning for now
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self._wait_any()
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return
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#print(' '.join(str(i) for i in self.history), end='')
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# handle debounce, which happens in both directions: press and release
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# - all samples must be in agreement to count as either
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for rc, count in enumerate(self.history):
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key = self.DECODER[rc]
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if count == 0 and key == self.key_pressed:
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# key up
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self._key_event('')
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break
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elif count == NUM_SAMPLES:
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self._key_event(key)
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break
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# do another scan
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self._start_scan()
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# EOF
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