firmware/shared/mempad.py
2019-02-08 12:32:04 -05:00

131 lines
3.6 KiB
Python

# (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
# and is covered by GPLv3 license found in COPYING.
#
# numpad.py - Numeric keypad. Touch button matrix.
#
import array, utime
from uasyncio.queues import Queue
from machine import Pin
from random import shuffle
from numpad import NumpadBase
_singleton = None
NUM_ROWS = const(4)
HISTORY_LEN = const(3)
class MembraneNumpad(NumpadBase):
def __init__(self, loop):
super(MembraneNumpad, self).__init__(loop)
global _singleton
assert not _singleton
_singleton = self
self.cols = [Pin(i, Pin.IN, pull=Pin.PULL_UP)
for i in ('M2_COL0', 'M2_COL1', 'M2_COL2')]
self.rows = [Pin(i, Pin.OUT_OD, value=0)
for i in ('M2_ROW0', 'M2_ROW1', 'M2_ROW2', 'M2_ROW3')]
# Scan in random order, because Tempest.
# However, we only scan where there is a touch, and we mustn't
# reveal which one by doing anything differently (in terms of scan).
self.scan_order = list(range(NUM_ROWS)) * HISTORY_LEN
shuffle(self.scan_order)
self.scan_idx = 0
self.history = []
self.wait_any = True
for c in self.cols:
c.irq(self.irq_handler, Pin.IRQ_FALLING|Pin.IRQ_RISING)
# ready to start
self.loop = loop
def irq_handler(self, pin):
# come here for any change, high or low
if self.wait_any:
# something was pressed, but we don't know what.. start a scan+debounce
self._start_scan()
def start(self):
# Begin scanning for events
self._disabled = False
self._wait_any()
def _wait_any(self):
# wait for any press.
for r in self.rows:
r.off()
self.wait_any = True
def _start_scan(self):
# reset and start a new scan
if self._disabled: return
self.history.clear()
self.wait_any = False
self.scan_idx = len(self.scan_order)-1
self._scan_next()
def _scan_next(self):
# enable detection on one row
active_row = self.scan_order[self.scan_idx]
for r, pin in enumerate(self.rows):
if r == active_row:
pin.off()
else:
pin.on()
# schedule an event for a little later
self.loop.call_later_ms(20, self._measure)
def _measure(self):
# sample the column values (unroll for simple)
if self.cols[0].value() == 0:
col_press = 0
elif self.cols[1].value() == 0:
col_press = 1
elif self.cols[2].value() == 0:
col_press = 2
else:
col_press = -1
if col_press != -1:
# anything down?
active_row = self.scan_order[self.scan_idx]
key = self.DECODER[(active_row, col_press)]
self.history.append(key)
print('+ ' + key)
if self.scan_idx:
self.scan_idx -= 1
self._scan_next()
return
# we're done a full scan (mulitple times: HISTORY_LEN)
if not self.history:
# all keys are up.
print('+quiet')
self._key_event('')
# stop scanning for now
self._wait_any()
else:
# perform debounce
# - do nothing if abiguous or in transition.
s = set(self.history)
if len(s) == 1:
self._key_event(self.history[0])
else:
print('bounce: ' + ' '.join(s))
self._start_scan()
# EOF