Beefy Boxes and Bandwidth Generously Provided by pair Networks
We don't bite newbies here... much
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
This 9th bit is generated internally by the UART based on the value of the parity bit. So, which parity bit is the Perl modules dealing with?

Perl does not do any parity, neither does any other language. The parity bit is generated and checked by the UART hardware. All that the OS and any language on top sees is a parity error if the check fails.

And do the modules allow this definition to be changed at will to drive the address function out onto the RS-485 bus?

That's an application of the mark and space "parity" bits. You could switch the serial format between "mark parity" and "space parity" to set or clear the parity bit from the application.

Of course it is possible to generate and verify the parity bit in the application, that's why some embedded U(S)ARTs allow 9 bit formats (8 bit plus application-specific use of the parity bit). On a generic PC-style USART, the data bits are limited to 8 bit, so if you want to use an application-specific parity bit, you are limited to 4 to 7 data bits.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

In reply to Re^4: How to read serial port with WIN32:SerialPort? by afoken
in thread How to read serial port with WIN32:SerialPort? by mastertone

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others avoiding work at the Monastery: (6)
As of 2022-05-27 18:50 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    Do you prefer to work remotely?



    Results (97 votes). Check out past polls.

    Notices?