Messages in this thread | | | Date | Fri, 27 Jul 2007 10:11:36 -0700 | From | Lee Howard <> | Subject | Re: serial flow control appears broken |
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Maciej W. Rozycki wrote:
>On Thu, 26 Jul 2007, Lee Howard wrote: > > > >>If the application were to use TIOCM_RTS how would it know when to apply it or >>not? Is there some approach that the application could take to manage flow >>control on the serial port? What about software flow control? Does the >> >> > > Well, an application could negate RTS when it receives a character and >is running out of resources for further processing of incoming data. > > Smarter UARTs may be able to negate RTS themselves based on the amount of >data in their receive FIFO. The threshold may be configurable. >
Okay, so let's say we've got a loop around a blocking read on the modem file descriptor...
for (;;) { read some data from modem process data from modem if (end-of-data detected) break; }
Are you suggesting that the application should be using deasserting RTS after the read and asserting it before?
I had previously thought that the control of RTS was something that the serial/tty driver was supposed to do independently based on the buffer fill. Was I wrong?
Thanks,
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