I have a device that sends a synchronous signal in a particular time interval.
I have used the pigpio library(monitor.py) to first match the durations of the pulses with that to an oscilloscope. And it is coming good .
Recognizing a signal train: It starts with a long low pulse of 61ms followed by a high pulse of 3.8 ms. After that the data bits starts.
Recognising the bits: bit 0- low duration of 3ms followed by high duration of 1ms.; bit 1- low duration of 1ms followed by high duration of 3ms.
monitor.py:
Below is my logic implementation inside the callback function:
the process data inside the cbf would be used later after getting the bits.
Problem: sometimes i am getting the bits correct and sometimes it is all just 1,1,1,1
how do can I change the logic something to like: First it would call the cbf, the data would be stored in a list and after two seconds it would break. Now with the achieved list i would Implement my logic and get the bits and process then. again call the cbf.
I have used the pigpio library(monitor.py) to first match the durations of the pulses with that to an oscilloscope. And it is coming good .
Recognizing a signal train: It starts with a long low pulse of 61ms followed by a high pulse of 3.8 ms. After that the data bits starts.
Recognising the bits: bit 0- low duration of 3ms followed by high duration of 1ms.; bit 1- low duration of 1ms followed by high duration of 3ms.
monitor.py:
Code:
import timeimport pigpiolast_tick = Noneduration_list = []def cbf(GPIO, level, tick): global last_tick, duration_list if last_tick is not None: diff = pigpio.tickDiff(last_tick, tick) print("G={} l={} d={}".format(GPIO, level, diff)) last_tick = tickpi = pigpio.pi()if not pi.connected: exit()# Add event detection for both rising and falling edges on GPIO 4cb = pi.callback(4, pigpio.EITHER_EDGE, cbf)try: while True: time.sleep(60)except KeyboardInterrupt: print("\nTidying up") cb.cancel() pi.stop()Code:
def cbf(GPIO, level, tick): global last, tick_start, bit_data, bit_start_seq, diff_data1, diff_data2, start_seq, Start_state if last[GPIO] is not None: diff = pigpio.tickDiff(last[GPIO], tick) rounded_diff = round_duration(diff) # print("G={} l={} d={}".format(GPIO, level, rounded_diff)) if rounded_diff > 61000: Start_state = True process_data(bit_data) print(bit_data) bit_data = [] if level != pigpio.TIMEOUT and rounded_diff < 3500 and Start_state: #and :tick_start != 0 if(pigpio.FALLING_EDGE): bit_start_seq += 1 if(bit_start_seq == 2): diff_data2 = rounded_diff if(pigpio.RISING_EDGE == 0 and bit_start_seq == 1): start_seq = True diff_data1 = rounded_diff if(start_seq and bit_start_seq == 2): if(diff_data1 > diff_data2): bit_data.append(0) else: bit_data.append(1) bit_start_seq = 0 start_seq = False last[GPIO] = tickProblem: sometimes i am getting the bits correct and sometimes it is all just 1,1,1,1
how do can I change the logic something to like: First it would call the cbf, the data would be stored in a list and after two seconds it would break. Now with the achieved list i would Implement my logic and get the bits and process then. again call the cbf.
Statistics: Posted by Axon_11 — Sun Apr 28, 2024 3:08 am