66 lines
2.6 KiB
Python
66 lines
2.6 KiB
Python
# shared/uart_comm.py
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import _thread
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from machine import UART
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import time
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class SafeUART:
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def __init__(self, uart_id, tx_pin, rx_pin, baudrate=115200):
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# Initialize the hardware UART channel
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self.uart = UART(uart_id, baudrate=baudrate, tx=tx_pin, rx=rx_pin, timeout=10)
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# Core thread-safety assets
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self.lock = _thread.allocate_lock()
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self.rx_queue = []
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self.buffer = b""
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# Start the background data worker thread
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_thread.stack_size(4096) # Cap the stack size for the UART listener
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_thread.start_new_thread(self._listener_worker, ())
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_thread.stack_size(0)
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print(f"[UART] Thread initialized on UART{uart_id} (TX:{tx_pin}, RX:{rx_pin})")
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def _listener_worker(self):
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"""Asynchronous internal loop parsing incoming stream lines into the queue."""
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while True:
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try:
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if self.uart.any():
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with self.lock:
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# Pull all raw bytes waiting in the hardware ring buffer
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chunk = self.uart.read(self.uart.any())
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if chunk:
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self.buffer += chunk
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# Process complete lines terminated by a newline character
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while b'\n' in self.buffer:
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line, self.buffer = self.buffer.split(b'\n', 1)
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try:
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decoded_line = line.decode('utf-8').strip()
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if decoded_line:
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self.rx_queue.append(decoded_line)
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except Exception:
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pass # Discard corrupt data frames safely
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except Exception as e:
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print("[UART Thread Error]:", e)
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time.sleep_ms(20) # Give other background threads breathing room
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def send(self, message):
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"""Safely pushes strings across the serial wire from any thread context."""
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if not message.endswith('\n'):
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message += '\n'
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with self.lock:
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self.uart.write(message.encode('utf-8'))
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def any(self):
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"""Checks if any complete messages are waiting to be read."""
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with self.lock:
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return len(self.rx_queue) > 0
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def read(self):
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"""Pulls the oldest unread string from the queue. Returns None if empty."""
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with self.lock:
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if self.rx_queue:
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return self.rx_queue.pop(0)
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return None |