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- palt-tilt-cam/PCA9685.py /
- @v-thiennp12
- v-thiennp12 Add files via upload
- Latest commit 99c7114 on 10 Aug 2020
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- 1 contributor
- 99 lines (84 sloc) 3.24 KB
-
- #!/usr/bin/python
-
- import time
- import math
- import smbus
-
- # ============================================================================
- # Raspi PCA9685 16-Channel PWM Servo Driver
- # ============================================================================
-
- class PCA9685:
-
- # Registers/etc.
- __SUBADR1 = 0x02
- __SUBADR2 = 0x03
- __SUBADR3 = 0x04
- __MODE1 = 0x00
- __MODE2 = 0x01
- __PRESCALE = 0xFE
- __LED0_ON_L = 0x06
- __LED0_ON_H = 0x07
- __LED0_OFF_L = 0x08
- __LED0_OFF_H = 0x09
- __ALLLED_ON_L = 0xFA
- __ALLLED_ON_H = 0xFB
- __ALLLED_OFF_L = 0xFC
- __ALLLED_OFF_H = 0xFD
-
-
- def __init__(self, address=0x40, debug=False):
- self.bus = smbus.SMBus(1)
- self.address = address
- self.debug = debug
- if (self.debug):
- print("Reseting PCA9685")
- self.write(self.__MODE1, 0x00)
-
- def write(self, reg, value):
- "Writes an 8-bit value to the specified register/address"
- self.bus.write_byte_data(self.address, reg, value)
- if (self.debug):
- print("I2C: Write 0x%02X to register 0x%02X" % (value, reg))
-
- def read(self, reg):
- "Read an unsigned byte from the I2C device"
- result = self.bus.read_byte_data(self.address, reg)
- if (self.debug):
- print("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
- return result
-
- def setPWMFreq(self, freq):
- "Sets the PWM frequency"
- prescaleval = 25000000.0 # 25MHz
- prescaleval /= 4096.0 # 12-bit
- prescaleval /= float(freq)
- prescaleval -= 1.0
- if (self.debug):
- print("Setting PWM frequency to %d Hz" % freq)
- print("Estimated pre-scale: %d" % prescaleval)
- prescale = math.floor(prescaleval + 0.5)
- if (self.debug):
- print("Final pre-scale: %d" % prescale)
-
- oldmode = self.read(self.__MODE1);
- newmode = (oldmode & 0x7F) | 0x10 # sleep
- self.write(self.__MODE1, newmode) # go to sleep
- self.write(self.__PRESCALE, int(math.floor(prescale)))
- self.write(self.__MODE1, oldmode)
- time.sleep(0.005)
- self.write(self.__MODE1, oldmode | 0x80)
- self.write(self.__MODE2, 0x04)
-
- def setPWM(self, channel, on, off):
- "Sets a single PWM channel"
- self.write(self.__LED0_ON_L+4*channel, on & 0xFF)
- self.write(self.__LED0_ON_H+4*channel, on >> 8)
- self.write(self.__LED0_OFF_L+4*channel, off & 0xFF)
- self.write(self.__LED0_OFF_H+4*channel, off >> 8)
- if (self.debug):
- print("channel: %d LED_ON: %d LED_OFF: %d" % (channel,on,off))
-
- def setServoPulse(self, channel, pulse):
- "Sets the Servo Pulse,The PWM frequency must be 50HZ"
- pulse = pulse*4096/20000 #PWM frequency is 50HZ,the period is 20000us
- self.setPWM(channel, 0, int(pulse))
-
- def setRotationAngle(self, channel, Angle):
- if(Angle >= 0 and Angle <= 180):
- temp = Angle * (2000 / 180) + 501
- self.setServoPulse(channel, temp)
- else:
- print("Angle out of range")
-
- def start_PCA9685(self):
- self.write(self.__MODE2, 0x04)
- #Just restore the stopped state that should be set for exit_PCA9685
-
- def exit_PCA9685(self):
- self.write(self.__MODE2, 0x00)#Please use initialization or __MODE2 =0x04
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