-
Notifications
You must be signed in to change notification settings - Fork 5
/
Copy pathPCA9685.py
129 lines (119 loc) · 5.29 KB
/
PCA9685.py
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
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
# Copyright (c) 2016 Adafruit Industries
# Author: Brian Norman
#
# Heavily based on Tony DiCola's driver at https://github.com/adafruit/Adafruit_Python_PCA9685/blob/master/Adafruit_PCA9685/PCA9685.py
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
from microbit import sleep, i2c
import math, ustruct
# Registers/etc:
PCA9685_ADDRESS = 0x40
MODE1 = 0x00
MODE2 = 0x01
SUBADR1 = 0x02
SUBADR2 = 0x03
SUBADR3 = 0x04
PRESCALE = 0xFE
LED0_ON_L = 0x06
LED0_ON_H = 0x07
LED0_OFF_L = 0x08
LED0_OFF_H = 0x09
ALL_LED_ON_L = 0xFA
ALL_LED_ON_H = 0xFB
ALL_LED_OFF_L = 0xFC
ALL_LED_OFF_H = 0xFD
# Bits:
RESTART = 0x80
SLEEP = 0x10
ALLCALL = 0x01
INVRT = 0x10
OUTDRV = 0x04
RESET = 0x00
class PCA9685(object):
"""PCA9685 PWM LED/servo controller."""
def __init__(self, i2c, address=PCA9685_ADDRESS):
"""Initialize the PCA9685."""
self.address = address
i2c.write(self.address, bytearray([MODE1, RESET])) # reset not sure if needed but other libraries do it
self.set_all_pwm(0, 0)
i2c.write(self.address, bytearray([MODE2, OUTDRV]))
i2c.write(self.address, bytearray([MODE1, ALLCALL]))
sleep(5) # wait for oscillator
i2c.write(self.address, bytearray([MODE1])) # write register we want to read from first
mode1 = i2c.read(self.address, 1)
mode1 = ustruct.unpack('<H', mode1)[0]
mode1 = mode1 & ~SLEEP # wake up (reset sleep)
i2c.write(self.address, bytearray([MODE1, mode1]))
sleep(5) # wait for oscillator
def set_pwm_freq(self, freq_hz):
"""Set the PWM frequency to the provided value in hertz."""
prescaleval = 25000000.0 # 25MHz
prescaleval /= 4096.0 # 12-bit
prescaleval /= float(freq_hz)
prescaleval -= 1.0
# print('Setting PWM frequency to {0} Hz'.format(freq_hz))
# print('Estimated pre-scale: {0}'.format(prescaleval))
prescale = int(math.floor(prescaleval + 0.5))
# print('Final pre-scale: {0}'.format(prescale))
i2c.write(self.address, bytearray([MODE1])) # write register we want to read from first
oldmode = i2c.read(self.address, 1)
oldmode = ustruct.unpack('<H', oldmode)[0]
newmode = (oldmode & 0x7F) | 0x10 # sleep
i2c.write(self.address, bytearray([MODE1, newmode])) # go to sleep
i2c.write(self.address, bytearray([PRESCALE, prescale]))
i2c.write(self.address, bytearray([MODE1, oldmode]))
sleep(5)
i2c.write(self.address, bytearray([MODE1, oldmode | 0x80]))
def set_pwm(self, channel, on, off):
"""Sets a single PWM channel."""
if on is None or off is None:
i2c.write(self.address, bytearray([LED0_ON_L+4*channel])) # write register we want to read from first
data = i2c.read(self.address, 4)
return ustruct.unpack('<HH', data)
i2c.write(self.address, bytearray([LED0_ON_L+4*channel, on & 0xFF]))
i2c.write(self.address, bytearray([LED0_ON_H+4*channel, on >> 8]))
i2c.write(self.address, bytearray([LED0_OFF_L+4*channel, off & 0xFF]))
i2c.write(self.address, bytearray([LED0_OFF_H+4*channel, off >> 8]))
def set_all_pwm(self, on, off):
"""Sets all PWM channels."""
i2c.write(self.address, bytearray([ALL_LED_ON_L, on & 0xFF]))
i2c.write(self.address, bytearray([ALL_LED_ON_H, on >> 8]))
i2c.write(self.address, bytearray([ALL_LED_OFF_L, off & 0xFF]))
i2c.write(self.address, bytearray([ALL_LED_OFF_H, off >> 8]))
def duty(self, index, value=None, invert=False):
if value is None:
pwm = self.set_pwm(index)
if pwm == (0, 4096):
value = 0
elif pwm == (4096, 0):
value = 4095
value = pwm[1]
if invert:
value = 4095 - value
return value
if not 0 <= value <= 4095:
raise ValueError("Out of range")
if invert:
value = 4095 - value
if value == 0:
self.set_pwm(index, 0, 4096)
elif value == 4095:
self.set_pwm(index, 4096, 0)
else:
self.set_pwm(index, 0, value)