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Merge pull request #539 from dayjaby/pr-fix_uart_startbit 

Fix UART startbit: 1 cycle later
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enjoy-digital 2020-05-25 10:33:58 +02:00 committed by GitHub
parent c75cf45ab4 e853ad4b61
commit 370e46529d
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1 changed files with 6 additions and 3 deletions
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9
litex/soc/cores/uart.py
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@ -99,8 +99,7 @@ class RS232PHYTX(Module):
If(self.sink.valid & ~tx_busy & ~self.sink.ready, If(self.sink.valid & ~tx_busy & ~self.sink.ready,
tx_reg.eq(self.sink.data), tx_reg.eq(self.sink.data),
tx_bitcount.eq(0), tx_bitcount.eq(0),
tx_busy.eq(1), tx_busy.eq(1)
pads.tx.eq(0)
).Elif(uart_clk_txen & tx_busy, ).Elif(uart_clk_txen & tx_busy,
tx_bitcount.eq(tx_bitcount + 1), tx_bitcount.eq(tx_bitcount + 1),
If(tx_bitcount == 8, If(tx_bitcount == 8,
@ -113,6 +112,10 @@ class RS232PHYTX(Module):
pads.tx.eq(tx_reg[0]), pads.tx.eq(tx_reg[0]),
tx_reg.eq(Cat(tx_reg[1:], 0)) tx_reg.eq(Cat(tx_reg[1:], 0))
) )
).Elif(tx_busy,
If(tx_bitcount == 0,
pads.tx.eq(0)
)
) )
] ]
self.sync += [ self.sync += [
@ -235,7 +238,7 @@ class UART(Module, AutoCSR, UARTInterface):
self._rxempty.status.eq(~rx_fifo.source.valid), self._rxempty.status.eq(~rx_fifo.source.valid),
self._rxtx.w.eq(rx_fifo.source.data), self._rxtx.w.eq(rx_fifo.source.data),
rx_fifo.source.ready.eq(self.ev.rx.clear | (rx_fifo_rx_we & self._rxtx.we)), rx_fifo.source.ready.eq(self.ev.rx.clear | (rx_fifo_rx_we & self._rxtx.we)),
# Generate RX IRQ when tx_fifo becomes non-empty # Generate RX IRQ when rx_fifo becomes non-empty
self.ev.rx.trigger.eq(~rx_fifo.source.valid) self.ev.rx.trigger.eq(~rx_fifo.source.valid)
] ]