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Home: Perl Programming Help: Beginner:
9 databits in Device::SerialPort

 


FPeter
Novice

Nov 9, 2012, 2:17 PM

Post #1 of 5 (4577 views)
9 databits in Device::SerialPort Can't Post
Hi All!

As i see, its not possible to set databits to 9 directly when using Device::SerialPort. Is there any way to read 9 bit frames from a special serial source? 9th bit means the starting of new packages, so it should be handled somehow... Is it possible to use the parity bit for this? Only reading is required, sending is not necessary...

Best regards


Laurent_R
Enthusiast / Moderator

Nov 10, 2012, 12:51 AM

Post #2 of 5 (4570 views)
Re: [FPeter] 9 databits in Device::SerialPort [In reply to] Can't Post
Hmm, not sure what you mean exactly by databits, but it could be that the number of bits has to be a power of 2.


FPeter
Novice

Nov 10, 2012, 1:06 AM

Post #3 of 5 (4569 views)
Re: [Laurent_R] 9 databits in Device::SerialPort [In reply to] Can't Post
in normal case, we use 8N1 mode, means 1 startbit + 8 databit + 1 stopbit

but now i need 1 startbit + 9 databit + 1 stopbit, where the 9th databit is a control bit. on PIC microcontrollers, You can write/read the parity bit register by software to implement the 9th bit - but i dont know if its possible in perl...


Laurent_R
Enthusiast / Moderator

Nov 10, 2012, 3:39 AM

Post #4 of 5 (4566 views)
Re: [FPeter] 9 databits in Device::SerialPort [In reply to] Can't Post
I had not seen that you were dealing with serial ports, and understood something different, therefore my previous answer was irrelevant.

I know nothing about serial ports, but the CPAN documentation (http://search.cpan.org/~cook/Device-SerialPort-1.000002/SerialPort.pm) seems to be saying:

Quote
databits

An integer from 5 to 8.


FPeter
Novice

Nov 10, 2012, 4:50 AM

Post #5 of 5 (4563 views)
Re: [Laurent_R] 9 databits in Device::SerialPort [In reply to] Can't Post
yes, it gives error message when i try to set databits parameter to 9

so im asking if there is an alternative roundabout to handle 9th bit, like soft reading of parity bit or any other way

 
 


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