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software/pwm_handler/upython/pwm_handler.py
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# -*- coding: utf-8 -*-
"""
author Benoit Dubois
licence GPL v3+
brief Main file of PWM controller (VNH5019 device).
"""
import pyb
import ujson
import serial_com as sc
import vnh5019
# Avoid use of timer 2, 3, 5 and 6
# see http://docs.micropython.org/en/latest/pyboard/library/pyb.Timer.html
TIMER_PWM_ID = 4
TIMER_PWM_FREQ = 1000
TIMER_PWM1_CH = 1
TIMER_PWM2_CH = 2
PIN_INA1 = 'PD5'
PIN_INB1 = 'PD6'
PIN_INA2 = 'PD1'
PIN_INB2 = 'PD2'
PIN_PWM1 = 'PB6'
PIN_PWM2 = 'PB7'
#----------------------------------------------------------
class MySerialCom(sc.SerialCom):
MNEMO_LIST = ["value"]
def decode_message(self, msg):
"""Message can be of type request or command.
Request message are made of a mnemonique followed by '?'.
Command message are made of 2 parts:
- a mnemonique,
- the value to be applied.
Each parts are separated with a space.
"""
if msg[:-1] == '?': # Request
return
else:
cmd = msg.split()
if len(cmd) != 3:
print("Decode error: bad command format")
return
mnemo = str(cmd[0])
if mnemo not in self.MNEMO_LIST:
print("Decode error: bad mnemonique")
return
num = int(cmd[1])
if num != 0 and num != 1:
print("Decode error: bad controller number")
return
try:
val = int(cmd[2])
except ValueError:
print("Decode error: bad command value")
return
return (mnemo, num, val)
#----------------------------------------------------------
class PwmHandler(object):
def __init__(self, config_filename):
self.scom = MySerialCom()
vnh0 = vnh5019.Vnh5019(in_a=PIN_INA1, in_b=PIN_INB1, pwm=PIN_PWM1,
timer=TIMER_PWM_ID, freq=TIMER_PWM_FREQ,
ch=TIMER_PWM1_CH)
vnh1 = vnh5019.Vnh5019(in_a=PIN_INA2, in_b=PIN_INB2, pwm=PIN_PWM2,
timer=TIMER_PWM_ID, freq=TIMER_PWM_FREQ,
ch=TIMER_PWM2_CH)
self.pwm = [vnh0, vnh1]
with open(config_filename, 'r') as f:
config = ujson.loads(f.read())
self.pwm[0].set_pwm_percent(config['val0'])
self.pwm[1].set_pwm_percent(config['val1'])
def apply_cmd(self, cmd):
if len(cmd) == 1: # Request
pass
else:
if cmd[0] == "value":
self.pwm[cmd[1]].set_pwm_percent(cmd[2])
def run(self):
while True:
self.scom.poller.poll(250)
if self.scom.vcom.any():
msg = self.scom.read_message()
if msg is not None:
cmd = self.scom.decode_message(msg)
if cmd is not None:
#print("pwm_handler.run.cmd:", cmd)
self.apply_cmd(cmd)
self.scom.write_message(msg)
#----------------------------------------------------------
if __name__=='__main__':
my_pwm = PwmHandler(config_filename='config.json')
my_pwm.run()
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