Bug with MPC55XX eSCI serial port byte size and parity?

Chris Johns chrisj at rtems.org
Sun Aug 24 02:24:56 UTC 2014

On 24/08/2014 5:22 am, Peter Dufault wrote:
> On Aug 23, 2014, at 09:56 , Joel Sherrill <Joel.Sherrill at oarcorp.com> wrote:
>> That all sounds very reasonable and since you have the hardware, you can check that it works. The interactive termios test is good for manually cycling through all the various settings. Change them on the target, then your comma program, see if the output is still right and then check another setting.
> My major question is how TERMIOS, data size, and parity should work.  To me it's vague.  If it's agreed that 7 bit data with parity is 8 bits of data and 8 bit data with parity is 9 bits of data then I'll make up a patch.

This is defined in the Open Group 
(https://www2.opengroup.org/ogsys/catalog/t101). In "Section 11.2.4 
Control Modes" it states:

  The CSIZE bits shall specify the number of transmitted or received
  bits per byte. If ISTRIP is not set, the value of all the other bits
  is unspecified. If ISTRIP is set, the value of all but the 7 low-order
  bits shall be zero, but the value of any other bits beyond CSIZE is
  unspecified when read. CSIZE shall not include the parity bit, if any.
  If CSTOPB is set, two stop bits shall be used; otherwise, one stop
  bit. For example, at 110 baud, two stop bits are normally used.

I hope this helps.


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