How to Configure Parity Error Control: Tutorial

This tutorial discusses the use of parity errors.

While it is normal in modern systems with error-corrected links to set serial ports up with no parity, there will be occasions when enabling detection of parity errors is both useful and desirable.

There are a number of different ways that parity errors can be handled:

  • ignore parity errors and discard any bytes with bad parity

  • replace bytes received with bad parity with the TCommConfigV01.iParityErrorChar character

  • immediately complete any read operation with a KErrCommsParity error

Use the TCommConfig package to change the value of iParityError and iParityErrorChar to change the parity settings.

Note: iParityError can be masked with KConfigXonXoffDebug. This has no effect on parity error control. It is an internal developmental debugging control which forces the high water mark to software flow control level of 5 bytes below 50% level instead the usual 75% level, irrespective of whether software flow control is enabled or not.