blob: 7461a5f916a9fdfa4bf28387b05aef06a255ce2b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
"""Hynitron CST816S touch contoller driver for MicroPython.
After modifying this file we can replace the frozen driver with the
test driver with the following command::
./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
|
