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Eugene Yong
03/09/07 04:05
Modified:
  03/09/07 04:40

Read: 1065 times
Malacca
Malaysia


 
#134632 - Why the need of circular buffer? Receiving?
Responding to: Russell Bull's previous message
How does the modem behave once it accepted a command and output a string response, let's say "OK"? Unlike the "send command" counterpart, there is no hardware mechanism to stop the the string("OK")from flowing into the SBUF (via RxD), is there? Therefore, how can i time and fetch the response of each character 'O' and 'K' respectively without missing any of them?

1. Is the flag RI alone sufficient to care of this job? Meaning, i will just configure SCON (specifically REN) to receive character and monitor RI for each successful sent character into the SBUF, transferring the SBUF content into a permanent location, and letting next character to be retrieved into SBUF. Does it works this way? (In another word, how does the modem knows that the SBUF is full and awaiting processing before it is allowed to send the next character)

Alternatively, would it be easier if i just configure the modem to output decimal value as response indication? (0 = "OK", 4 = "ERROR", 6 = "NO DIALTONE", etc.) By doing this, i do not have to worry about receiving multi-bytes data.


2. Or is this where circular buffer comes into play? I do not really understand about how is this being used, i hope you would be kind enough to elaborate a little more about this :) Yes i have read a little about circular buffer and how it works but i cant seem to relate it to my problem at the moment.


P/S-The code suggested by you was obviously clearer and easier to manipulate as you have mentioned. Thanks for the tips!

List of 72 messages in thread
TopicAuthorDate
Serial Communication Related Problem        Eugene Yong      03/06/07 10:49      
   partial answers      Patrick De Groote      03/06/07 11:07      
      Oh yeah, i forgot about that      Eugene Yong      03/06/07 12:09      
   FIRST, THEN, THEN, THEN      Erik Malund      03/06/07 11:10      
      A little bit of sarcasm as usual but often helpful      Eugene Yong      03/06/07 12:25      
         Proper baud rate...      Dave Brooks      03/06/07 12:52      
            baud rate      Erik Malund      03/06/07 13:01      
               calculator      Dave Brooks      03/06/07 13:11      
            modem is autobauding      Jan Waclawek      03/06/07 16:04      
               Noted      Eugene Yong      03/06/07 21:00      
   Some answers      Lynn Reed      03/06/07 11:14      
      Thanks for a patience reply      Eugene Yong      03/06/07 12:33      
   Nothing to add, but ...      Joseph Hebert      03/06/07 11:29      
      i second(ed) that motion      Erik Malund      03/06/07 11:44      
         My location profile?      Eugene Yong      03/06/07 12:38      
            with this known, it would do no good ...      Erik Malund      03/06/07 12:40      
               Radio Shack      Lynn Reed      03/06/07 12:45      
                  Even so      Neil Kurzman      03/06/07 20:44      
                     I can buy it from the local electronic shop      Eugene Yong      03/06/07 20:52      
            Sarcasm      Neil Kurzman      03/06/07 20:52      
               I agree      Eugene Yong      03/06/07 20:57      
      Thanks for understanding and recommendation! - NT      Eugene Yong      03/06/07 12:35      
      More info      Russell Bull      03/06/07 22:28      
         you need to understand the parameters.      Mike Stegmaier      03/07/07 06:28      
            "more valid" evidently means invalid      Erik Malund      03/07/07 07:04      
            not quite      Patrick De Groote      03/07/07 07:29      
               What a wonderful example that when total crap is s      Erik Malund      03/07/07 07:44      
                  lesson      Patrick De Groote      03/07/07 11:43      
            No, it doesn't      Andy Neil      04/03/07 00:37      
   TxD pin to TxD pin?      Eugene Yong      03/07/07 15:31      
      dte-dce-dce-dte      Patrick De Groote      03/07/07 16:00      
         Noted! Thanks!      Eugene Yong      03/07/07 16:20      
            same request question      Jecksons Ben      03/07/07 21:38      
      Meaning of "Transmit"      Andy Neil      04/03/07 04:37      
   same request question 2      Jecksons Ben      03/07/07 21:54      
   Initial command sending code; help me take a look!      Eugene Yong      03/09/07 01:50      
      Make it simple for yourself      Russell Bull      03/09/07 02:50      
         Why the need of circular buffer? Receiving?      Eugene Yong      03/09/07 04:05      
            polling versus interrupt      Patrick De Groote      03/09/07 05:17      
               Check OK string at RXD or DCD at interupt?      Jecksons Ben      03/09/07 21:27      
                  no good      Patrick De Groote      03/10/07 02:14      
                     Voice mode only! No data communication.      Eugene Yong      03/10/07 04:09      
                        you are missing the basics      Patrick De Groote      03/10/07 04:26      
                           NO carrier sent after DCD didn't found      Jecksons Ben      03/11/07 19:54      
                              I do not agree      Patrick De Groote      03/12/07 00:37      
                                 Interupt DCD signal for clear transmission      Jecksons Ben      03/15/07 01:15      
                        For Voice Dialling      Muhammad Fauzan      03/19/07 12:33      
                           and by the way      Muhammad Fauzan      03/19/07 12:36      
                           Sorry for multiposting      Muhammad Fauzan      03/19/07 12:58      
                           The ";" works but...      Eugene Yong      03/22/07 19:46      
                              ";" to return to idle state      Muhammad Fauzan      03/24/07 16:48      
                              +++ with 3 seconds no modem activity      Charles Bannister      03/25/07 03:41      
                                 +++ escape sequence      Andy Neil      03/25/07 07:07      
                                    Monkey See. Monkey Do.      Charles Bannister      03/25/07 08:14      
                                       Now monkey also understand?      Andy Neil      03/26/07 00:26      
                                 Are you mistaken?      Eugene Yong      03/25/07 23:36      
                                    I think so      Andy Neil      03/26/07 00:24      
            Circular buffers      Russell Bull      03/23/07 00:42      
               Initial code for receiving modem response      Eugene Yong      03/26/07 10:38      
                  don't fiddle with the timer, let it run      Erik Malund      03/26/07 10:43      
                     Understood, will run TR1 in global init, thx! - NT      Eugene Yong      03/26/07 10:48      
                  check this out, Eugene...      Dave Brooks      03/26/07 10:52      
                     Ah! Didn't know that! Thanks! -NT      Eugene Yong      03/26/07 11:09      
                     Code; modem commands & responses      Andy Neil      03/26/07 11:23      
   V.250 (formerly V.25-ter) - get it free!      Andy Neil      03/26/07 14:28      
   code,modem command and response      Jecksons Ben      04/01/07 20:20      
   system froze when connected to hyperterminal      Eugene Yong      04/02/07 13:39      
      Your code...      Russell Bull      04/02/07 23:48      
         It should not be a hardware problem since..      Eugene Yong      04/03/07 01:43      
            Not necessarily      Andy Neil      04/03/07 02:42      
      Just taking a stab at it...      Chris Singer      04/03/07 10:22      
         two 'ugly' guesses      Erik Malund      04/03/07 10:44      

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