Communications Guru?
I am having issues with output being trashed when communicating to a device
which does not support hardware flow control. I have disabled ALL hardware
flow control in Dev.ser and with /dev/ser1 & /dev/ser2. RTS is high, CTS is
low and CD is low when cable is connected to device. If I take the (device
end) cable and connect it to /dev/ser2 (forming a loopback to /dev/ser1) CTS
and CD both go high and sending a receiving data can be peformed at the
given baud rate without errors and without delays.
If I place a delay(250) before sending each request to the device, it works.
Keep in mind that I cannot send another request until the device responses,
so the device flow controls me. I.e.,
Poll … Receive
delay(250)
Poll … Receive, etc.
If I comment out the delay(250) or make it any smaller value, the output is
not received by the device correctly. Interesting to note that the same
program written under Microsoft Windows does not exhibit these problems.
ANY IDEAS???
Larry Fly
“Larry Fly” <lfly@earthlink.net> wrote in message
news:ahhgpo$m8r$1@inn.qnx.com…
Communications Guru?
I am having issues with output being trashed when communicating to a
device
which does not support hardware flow control. I have disabled ALL
hardware
flow control in Dev.ser and with /dev/ser1 & /dev/ser2. RTS is high, CTS
is
low and CD is low when cable is connected to device. If I take the
(device
end) cable and connect it to /dev/ser2 (forming a loopback to /dev/ser1)
CTS
and CD both go high and sending a receiving data can be peformed at the
given baud rate without errors and without delays.
If I place a delay(250) before sending each request to the device, it
works.
Keep in mind that I cannot send another request until the device
responses,
so the device flow controls me. I.e.,
Poll … Receive
delay(250)
Poll … Receive, etc.
When the devices has returned the last bytes of its response how fast
is it ready to accept your next command? It may take the device some
“time” to get ready?
If I comment out the delay(250) or make it any smaller value, the output
is
not received by the device correctly. Interesting to note that the same
program written under Microsoft Windows does not exhibit these problems.
ANY IDEAS???
Larry Fly