Roy
90 lines
2.2 KiB
Python
90 lines
2.2 KiB
Python
from time import sleep
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from typing import Optional
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import serial
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from . import LowLevelHardwareInterface
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SerialTimeoutException = serial.SerialTimeoutException
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class UARTInterface(LowLevelHardwareInterface):
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"""USB serial interface.
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if device not found, raise SerialException.
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"""
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__slots__ = ('_port', '_baudrate', '_serial')
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def __init__(self, port: str, baudrate: int = 115200):
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self._port = port
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self._baudrate = baudrate
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self._serial: serial.Serial = None
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def reset(self):
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if self._serial is not None and not self._serial.closed:
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self._serial.close()
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self._serial = serial.Serial(self._port,
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baudrate=self._baudrate,
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timeout=0,
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writeTimeout=0.01)
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# deprecate function name which change at version 3.0
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self._serial.flushInput()
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self._serial.flushOutput()
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def close(self):
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if self._serial is not None and not self._serial.closed:
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self._serial.close()
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self._serial = None
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def flush(self):
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self._serial.flush()
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def flush_input(self):
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self._serial.flushInput()
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def flush_output(self):
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self._serial.flushOutput()
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def send_byte(self, data: bytes):
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"""send raw byte instruction to the hardware
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:param data: raw byte instruction
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:raises SerialTimeoutException:
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"""
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self._serial.write(data)
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def recv_byte(self, size: int) -> Optional[bytes]:
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"""receive raw byte data from hardware.
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:param size: number of bytes want to receive
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:return: raw byte data, None if fail.
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"""
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return self._serial.read(size)
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def _main():
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uart = UARTInterface('/dev/ttyAMA0')
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uart.reset()
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try:
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while True:
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try:
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uart.send_byte("1234".encode())
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except SerialTimeoutException:
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pass
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result = uart.recv_byte(4)
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if result is not None:
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print(result.decode())
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sleep(1)
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except KeyboardInterrupt:
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pass
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if __name__ == '__main__':
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_main()
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