On 3/9/06, Matthew Percival <matthew@xxxxxxxxx> wrote: > G'Day, > > I am writing a script (in Lua) to transmit to/read from a serial device > (in this case, a GSM modem). Whilst I have no difficulty with most > normal aspects (eg transmit AT, read back OK), I seem unable to use the > SMS properly. As a brief description of what should happen, I transmit > `AT+CMGS=(phone number)' and receive back a `> ' prompt to let me know > it is ready for the message. If I send that line and the message in > interactive mode (waiting to see the `> ' appear in minicom before > sending the message), then it works fine (so the basic concept seems to > be right), but I cannot seem to script this. > > If I try to read back from the device one character at a time (after > sending the AT+CMGS line), I get two blanks then it blocks. If I look > on a terminal program, I can see that after I sent the command, there > was a carriage return and a line feed, then on the next line was the > > and (space) for the prompt. This suggests to me that I am reading the > CR and the LF, but it blocks when it tries to read the next line, which > has no control characters terminating it (after all, it is a prompts). > > My question, to anyone who knows the way the serial driver works, is: > can I read back from the device a single character, or does the driver > only buffer a complete line, defined as being 0 or more characters > ending in a control character (or something like that)? My observation > seems to be that I can read anything that ends in a control character, > but nothing that does not. > Hi Matthew- The problem is an issue of the serial port being in "cooked" mode - the driver doesn't deliver the characters in the buttern until either a carriage return or a line feed (I forget which one) is received. There is a way to put the driver into "raw" mode, which delivers every single character immediately. However, I don't have any example code in front of me, and the only example code that I have is in C. I can forward you the example code a little later today, if you are intereseted. I'm surry there's a way to do it via command-line/script, I just don't know it off the top of my head. -James > Thanks for your time, > > Matthew > > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
