Hi Thanassis - if there is no reply here, you might try joining and posting on the meta-freescale mailing list (https://lists.yoctoproject.org/listinfo/meta-freescale)
On Thu, Jul 4, 2013 at 7:24 AM, Thanassis Silis <djnass...@hotmail.com> wrote: > > > ________________________________ > From: djnass...@hotmail.com > To: meta-freesc...@yoctoproject.org > Date: Thu, 4 Jul 2013 13:40:10 +0000 > Subject: [meta-freescale] serial port timeout before expected # of bytes > arrives > > Hello everyone, > I am trying to port an application that is receiving/sending data through > the serial port. > On the sabrelite board that is the /dev/ttymxc0 port, ie the 2ndary serial > port (the primary being /dev/ttymxc1). > > I am using the functions select() and read() to read from the serial port , > in order to implement a timeout mechanism that is waiting for a few seconds > for bytes to arrive and if should they not arrive, then the timeout is > reached. > > The receiving loop works like this: > > I wait for 2 bytes - the opcode of the command. > Once I resolve a code, I wait for 4 bytes designating the length of data > that will follow (depending on the command) > I create a buffer in my application of size equal to the length I received > above. > I start receiving the data. > > > > Note that I have implemented reception of the data in 2 ways (since the 1st > way used to work, it was tried as is. Then, I tried the next as well): > > > > a)receive my data using a for loop, reading() one byte at time. until all > the expected bytes arrive , or a timeout is reached. > > b)receive my data using a while loop where I ask for all the remaining bytes > to be read(). Read() returns how many bytes have actually arrived, so I > update the remaining Bytes and re-read(). Again if a select() times-out > without any data arriving, the loop will exit. > > > Now, my problem is that while applications seem to be using this port > without any problem (f.e. minicom, rx, cat /dev/ttymxc0, echo "something" > > /dev/ttymxc0 ) , through the application I get timeouts for any file that is > bigger than 3-4kBytes. > > > Say I am trying to send a file 138kB. I may fail at byte ~40k, ~56k, or even > ~12k. This is very weird. And I don't know what to assume is going wrong. > Slow processing on the local end seems to not be a problem, as I can read > (in (b) above) approx 58 bytes in the beginning and then 1 byte at a time. > Could it be the memory buffer? If yes, how can I increase its size? Could > another application be interfering with /dev/ttymxc0? > > > > I am running fsl-image-test with all -dev, -sdk & -dbg options enabled. > > > Thank you for your help. > > > > > > > > _______________________________________________ meta-freescale mailing list > meta-freesc...@yoctoproject.org > https://lists.yoctoproject.org/listinfo/meta-freescale > > _______________________________________________ > yocto mailing list > yocto@yoctoproject.org > https://lists.yoctoproject.org/listinfo/yocto > -- Jeff Osier-Mixon http://jefro.net/blog Yocto Project Community Manager @Intel http://yoctoproject.org _______________________________________________ yocto mailing list yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/yocto
