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38 lines
775 B
Python
38 lines
775 B
Python
from myhdl import delay, intbv, downrange
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from rs232_util import sec, parity, ParityError, StopBitError
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def rs232_rx(rx, actual, cfg):
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""" rs232 receiver.
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rx -- serial input data
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actual -- data actually received
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cfg -- rs232_util.Config configuration object
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"""
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data = intbv(0)
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period = int(1*sec / cfg.baud_rate)
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yield rx.posedge
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yield delay(period // 2)
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data[7] = 0
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for i in downrange(cfg.n_bits):
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yield delay(period)
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data[i] = rx
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if cfg.parity is not None:
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yield delay(period)
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if rx != parity(data, cfg.parity):
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raise ParityError
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yield delay(period)
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if rx != 0:
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raise StopBitError
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actual[8:] = data
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