[Xenomai-help] RT Serial, rt_dev_read blocking problem

[Dehann Fourie <dehann.fourie@domain.hid>]

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Hi,

I am having trouble with reading data from the serial port. I initially
followed the RT Serial example from captain. I changed the read task to a
periodic 20ms task, from which I read from the serial port (rtser0). This is
all that the rt_task is doing. The serial port config is:

static const struct rtser_config
<http://www.xenomai.org/documentation/trunk/html/api/structrtser__config.html>
read_config = {
        .config_mask       = 0xFFFF,
        .baud_rate         = 57600,
        .parity            = RTSER_NO_PARITY,
        .data_bits         = RTSER_8_BITS,
        .stop_bits         = RTSER_1_STOPB,
        .handshake         = RTSER_NO_HAND,
        .fifo_depth        = RTSER_DEF_FIFO_DEPTH,
        .rx_timeout        = RTSER_DEF_TIMEOUT,
        .tx_timeout        = RTSER_DEF_TIMEOUT,
        .event_timeout     = RTSER_DEF_TIMEOUT,
        .timestamp_history = RTSER_RX_TIMESTAMP_HISTORY,
        .event_mask        = RTSER_EVENT_RXPEND,
};

I am reading data into a buffer, char buf[300]. I am able to read data but
the task is repeating at a rate of about 50ms. Execution also only returns
from the rt_dev_read() call when 300 chars have been read, but the external
hardware is only sending a couple of chars (+-35) at a rate of 171Hz. Is the
rt task maybe blocking? How can I get it to only read the available chars in
the serial buffer and then return to my program?

I am on a Geode 500MHz single board computer with kernel 2.6.23 and xeno
2.4.3.

Thanks in advance.

Kind regards,

-- 
Dehann Fourie

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