Serial Port Woes
I'm having a lot of trouble consistently reading a serial port. I'm trying to talk to a microcontroller using ModBus ASCII and the basic idea is to send a request for data (about 12 bytes) and then wait for an answer (about 300 bytes). There is between a 1/4 and 1/2 second delay from when I send the command and the controller STARTS sending it back. I also can't get it to work at all if I open it for update (either text or binary). I have to open the com port, send the command, then close the port and reopen it for read to get anything at all. I've tried until linefeed, until empty, until eof, for 1 line, etc. and none of them seem to work reliably. I KNOW that a response ends with a CRLF pair and there is only ever 1 line in a response so if I could just wait until I got the LF and it happened in say 3 seconds or less, I'd be happy. Any suggestions?? len morgan ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Serial Port Woes
I was working on a serial port stack but have been prevented from programming on it for over a year now due to being poisoned and tormented in my own home by a communist nazi like secret society destroying select lives in America. It is unfinished but it does some basic calls. If you are interested I will put it on the Rev site and allow anyone to use or improve it. -=JB=- On Jan 12, 2010, at 7:40 AM, Len Morgan wrote: I'm having a lot of trouble consistently reading a serial port. I'm trying to talk to a microcontroller using ModBus ASCII and the basic idea is to send a request for data (about 12 bytes) and then wait for an answer (about 300 bytes). There is between a 1/4 and 1/2 second delay from when I send the command and the controller STARTS sending it back. I also can't get it to work at all if I open it for update (either text or binary). I have to open the com port, send the command, then close the port and reopen it for read to get anything at all. I've tried until linefeed, until empty, until eof, for 1 line, etc. and none of them seem to work reliably. I KNOW that a response ends with a CRLF pair and there is only ever 1 line in a response so if I could just wait until I got the LF and it happened in say 3 seconds or less, I'd be happy. Any suggestions?? len morgan ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Serial Port Woes
On Wed, Jan 13, 2010 at 1:40 AM, Len Morgan len-mor...@crcom.net wrote: I'm having a lot of trouble consistently reading a serial port. I'm trying to talk to a microcontroller using ModBus ASCII and the basic idea is to send a request for data (about 12 bytes) and then wait for an answer (about 300 bytes). There is between a 1/4 and 1/2 second delay from when I send the command and the controller STARTS sending it back. I also can't get it to work at all if I open it for update (either text or binary). I have to open the com port, send the command, then close the port and reopen it for read to get anything at all. I've tried until linefeed, until empty, until eof, for 1 line, etc. and none of them seem to work reliably. I KNOW that a response ends with a CRLF pair and there is only ever 1 line in a response so if I could just wait until I got the LF and it happened in say 3 seconds or less, I'd be happy. Hi Len, I have done a lot of work with serial ports, and although I always put in lots of checks that close re-open the port if there is an error, this is not a normal occurrence. Have a look at my serial test stack http://www.troz.net/rev/stacks/SerialTest.rev which allows you to configure the expected line endings as well as all the serial port parameters. It sends data, and then constantly checks for incoming responses from the serial device. Cheers, Sarah ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
Re: Serial Port Woes
I'd love to take a stab at finishing it up. If you have any thoughts on what you feel is missing that you didn't get a chance to finish, let me know. Maybe I can release a serial library we could all use. len morgan On 1/12/2010 12:26 PM, -= JB =- wrote: I was working on a serial port stack but have been prevented from programming on it for over a year now due to being poisoned and tormented in my own home by a communist nazi like secret society destroying select lives in America. It is unfinished but it does some basic calls. If you are interested I will put it on the Rev site and allow anyone to use or improve it. -=JB=- On Jan 12, 2010, at 7:40 AM, Len Morgan wrote: I'm having a lot of trouble consistently reading a serial port. I'm trying to talk to a microcontroller using ModBus ASCII and the basic idea is to send a request for data (about 12 bytes) and then wait for an answer (about 300 bytes). There is between a 1/4 and 1/2 second delay from when I send the command and the controller STARTS sending it back. I also can't get it to work at all if I open it for update (either text or binary). I have to open the com port, send the command, then close the port and reopen it for read to get anything at all. I've tried until linefeed, until empty, until eof, for 1 line, etc. and none of them seem to work reliably. I KNOW that a response ends with a CRLF pair and there is only ever 1 line in a response so if I could just wait until I got the LF and it happened in say 3 seconds or less, I'd be happy. Any suggestions?? len morgan ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution ___ use-revolution mailing list use-revolution@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
