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.