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48 lines
1.0 KiB
Python
48 lines
1.0 KiB
Python
import operator
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from myhdl import *
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from rs232_util import reduceXor, sec, ODD, EVEN, MARK, SPACE
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def rs232_tx(tx, data, cfg):
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""" rs232 transmitter.
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tx -- serial output data
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data -- input data byte to be transmitted
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cfg -- rs232_util.Config configuration object
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"""
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duration = delay(int(1*sec / cfg.baud_rate))
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@instance
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def logic():
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tx.next = 1
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yield duration
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for i in downrange(cfg.n_bits):
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tx.next = data[i]
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yield duration
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if cfg.parity is not None:
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if cfg.n_bits == 7:
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data[7] = 0
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if cfg.parity == ODD:
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tx.next = not reduceXor(data[8:])
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elif cfg.parity == EVEN:
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tx.next = reduceXor(data[8:])
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elif cfg.parity == MARK:
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tx.next = 1
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elif cfg.parity == SPACE:
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tx.next = 0
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yield duration
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tx.next = 0
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for i in range(cfg.n_stops):
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yield duration
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return logic
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