Parity and Stop Bits of SoftwareSerial

Projects Networking, Protocols, and Devices
1

Hi,

does anyone know the parity and number of stop bits for the from
SoftwareSerial emulated UART port?

Thanks

2

A quick look at the source code on github and it doesn't look like there's any code to support a parity bit or stop bit(s) on Tx or Rx. Stop bit(s) may be there as a result of the delay between bytes due to software emulation.

3

Hi,
I think 8N1 should be the standard, but I'm not sure.

4

Source code seems to agree :wink:

  // Write each of the 8 bits
  for (uint8_t i = 8; i > 0; --i)
  {
    if (b & 1) // choose bit
      *reg |= reg_mask; // send 1
    else
      *reg &= inv_mask; // send 0

    tunedDelay(delay);
    b >>= 1;
  }

...
...

  tunedDelay(_tx_delay);

The last tunedDelay should be the stop bit. There is no sign of parity

1 Like
5

Thanks

6

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