Thank you Frédéric for your suggestion!
I am looking into the datasheet in order to discover these values.
BTW the QtSerialPort library doesn't report anything and from its side
everithing is working properly...
This could be a serial port library bug or a driver issue???
I think that there is no clear border, but the low level library
implementation (I mean the unix system call invoked from library) may be
better managed in order to check that the port is properly set to the
requested frequency...
Stefano.
On 10/18/2013 01:02 PM, Frédéric Marchal wrote:
Hi list,
I am trying to communicate via serial port with a device that use
125000 bps.
When I set the custom baud rate the setBaudRate return true without
error (I also check with debugger and the QSerialPortPrivateData
inputBaudRate and outputBaudRate are properly set to 125000).
But when I check with an oscilloscope the frequency of bits that came
out from serial port the result is that the port is set to 115200...
After sending data through serial port I print the port baudRate() and
the value is even set to 125000.
I am using Qt 4.8.4 (for project reason) under linux.
Any ideas about this problem?
Is your serial port capable of emitting at a baud rate of 125kbaud?
UARTs often produce the requested baud rate by dividing an internal oscillator
by an integer number. As such, they can only attain a fixed set of baud rates.
For instance, an internal oscillator at 460KHz can be divided by 4 to emit at
115kbaud but it cannot generate a clock at 125kbaud.
I have seen drivers that reports an error if the requested baud rate is
unavailable while other silently selects the closest attainable baud rate.
Frederic
--
*Stefano Cordibella*
EDALab s.r.l. - Networked Embedded Systems
Strada Le Grazie, 15 - 37134 Verona - Italy
email : stefano.cordibe...@edalab.it
skype : stefano.cordibella
tel. : +39 045 802 70 85
web : www.edalab.it
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