68 lines
1.8 KiB
Python
68 lines
1.8 KiB
Python
# SPDX-License-Identifier: LGPL-3.0-or-later
|
|
# Copyright (C) 2020 Daniel Thompson
|
|
|
|
"""Hynitron CST816S touch contoller driver for MicroPython.
|
|
|
|
After modifying this file we can test the changes by replacing the
|
|
frozen driver with the modified driver. The following command will
|
|
upload the code and integrate it into the watch namespace::
|
|
|
|
./tools/wasptool\
|
|
--exec wasp/drivers/cst816s.py\
|
|
--eval "watch.touch = CST816S(watch.i2c)"`
|
|
"""
|
|
|
|
import array
|
|
|
|
class CST816S:
|
|
"""Hynitron CST816S I2C touch controller driver."""
|
|
|
|
def __init__(self, bus):
|
|
self.i2c = bus
|
|
self.dbuf = bytearray(6)
|
|
self.event = array.array('H', (0, 0, 0))
|
|
|
|
def get_event(self):
|
|
"""Receive a touch event.
|
|
|
|
Check for a pending touch event and, if an event is pending,
|
|
prepare it ready to go in the event queue.
|
|
|
|
:return: An event record if an event is received, None otherwise.
|
|
"""
|
|
dbuf = self.dbuf
|
|
event = self.event
|
|
|
|
# TODO: check the interrupt pin
|
|
|
|
try:
|
|
self.i2c.readfrom_mem_into(21, 1, dbuf)
|
|
except OSError:
|
|
return None
|
|
|
|
# Skip junk events
|
|
if dbuf[0] == 0:
|
|
return None
|
|
|
|
x = ((dbuf[2] & 0xf) << 8) + dbuf[3]
|
|
y = ((dbuf[4] & 0xf) << 8) + dbuf[5]
|
|
swipe_start = dbuf[2] & 0x80
|
|
|
|
# Skip identical events... when the I2C interface comes alive
|
|
# we can still get back stale events
|
|
if dbuf[0] == event[0] and x == event[1] and y == event[2] \
|
|
and not swipe_start:
|
|
return None
|
|
|
|
# This is a good event, lets save it
|
|
event[0] = dbuf[0]
|
|
event[1] = x
|
|
event[2] = y
|
|
|
|
# Do not forward swipe start events
|
|
if dbuf[2] & 0x80:
|
|
event[0] = 0
|
|
return None
|
|
|
|
return event
|