Re: Optimizing reading from Serial Port

Martin, Anabel wrote:
> 	We are communicating with an Omron PLC through TINI's serial
> port using a baudrate of 19200 bps. Our application sends some commands
> to the PLC and wait for the answers. We have tested the application with
> the PC and with TINI and we can observe some differences in the time
> that is needed to read data from serial port:
> 		- PC: 2,3 ms
> 		- TINI: 15 ms
> 
> 	What reason could cause that difference?

Several factors may be involved including serial latency and parse overhead.

>        outStream.write(commands); // Transmit the commands
Possibly follow this write by a flush().

>      timer = timeOut + TINIOS.uptimeMillis();
>    while (System.currentTimeMillis() < timer && !finished) {
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
Make this uptimeMillis().

>              for (count = index; count < (bytesCount + index); count++)
                                            ^^^^^^^^^^^^^^^^^^^
Take this loop invariant out of the loop like this:
maxindex = bytesCount + index;
for (count = index; count < maxindex; count++)

>                if (buffer [count] == RETURN) {
                                        ^^^^^^
Make sure these constant type values are declared static final so that 
the code is inlined and no instance fields must be accessed.

-Bryan

-- 
--
Bryan Armstrong
bryan.armstrong-6tN4nzCoH/[email protected]


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