Trouble with RS-232 BS2px on Professional Development board.

Comments

• Bruce Bates Posts: 3,045

  2006-01-26 19:39 edited 2006-01-26 19:39

  Rickard -
  
  You are sending the command once, then fetching the reply once. That apears to work okay, but then you go back to re-fetch the reply again and again, without issuing another command. Is that what you really want to be doing. or do you want to send the command, receive a reply, and then go back and repeat the ENTIRE process? If so, the last instruction should be GOTO Start, not GOTO Main.
  
  Regards,
  
  Bruce Bates
• Jon Williams Posts: 6,491

  2006-01-26 19:52 edited 2006-01-26 19:52

  Since you're using a BS2px I suggest you use the SPSTR modifier to buffer the modem output into the Scratchpad;·trying to catch characters one at a time in a loop like you're doing is not going to be reliable.
  
  You might want to add a Conditional Compilation block to set the baudmode as well -- this will make it easier to experiment with different baud rates and ensure you get the right values in the program.· I've attached a StampWorks 2 program that uses the external serial port on the PDB (with flow control).· It has a CC block that you can paste write into your program.
  
  In the end, you might end up with something like this:
  
  · SERIN Rx, Baud, (SPSTR 58)··· ' capture 58 characters from modem
  · FOR idx = 0 TO 57·············' display capture
  ··· GET idx, char
  ··· DEBUG char
  · NEXT
  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  Jon Williams
  Applications Engineer, Parallax

  TXT

  TXT

  SW20-EX34-Serial_IO.BS2.TXT

  9K

  SW20-EX34-Serial_IO.BS2.TXT 9.1K
• Firestone1 Posts: 5

  2006-01-26 20:14 edited 2006-01-26 20:14

  Thanks for the rapid answers!
  
  Bruce: Yes I know. This was just a test loop but thanks for the note. I have restarted the program for every run.
  
  Jon:·Many thanks for the tip.·I'll try that and see what I get. (Its 9pm here in sweden and I have promised my family some really late dinner..:-))
  
  I'll get back...
  
  /Rickard
• Firestone1 Posts: 5

  2006-01-26 22:59 edited 2006-01-26 22:59

  Still no luck..
  
  I thougt I noticed a change when I hade the board turned off for a while. Then I got three correct answers in a row before getting a wrong one. It's like the stamp doesn't get the first bit and then go wild for a while. Then there is a small break before the modem writes OK and the stamp have time to catch up.
  
  Can I in some way se if the flowcontrol works as it should? I cant see any kind of difference.
  
  Wrote the output in hex to see if it is a bit swap of some kind but I haven't found a pattern yet anyway..
  
  Faulty:
  
  48 68 29 A 25 A5 2 42 82 62 9A 82 82 62 8A 92 82 82 62 92 A2 82 82 62 A2 C2
  82 82 62 CA B2 82 82 62 8A CA 92 82 82 62 9A C2 A2 82 82 62 AA BA B2 82 82 6
  2 8A 8A AA 92 82 82 4A 6A A
  
  Correct:
  
  A 2B 49 50 52 3A 20 28 30 2C 33 30 30 2C 31 32 30 30 2C 32 34 30 30 2C 34 38
  30 30 2C 39 36 30 30 2C 31 39 32 30 30 2C 33 38 34 30 30 2C 35 37 36 30 30
  2C 31 31 35 32 30 30 29 D A
  
  

  ' {$STAMP BS2px}
  ' {$PBASIC 2.5}
  
  test VAR Byte
  idx VAR Byte
  start:
  PAUSE  3000
  SEROUT 3, 3313, [noparse][[/noparse]"AT+IPR=?", CR, LF ]
  SERIN 1\2, 3313, 2000,GoOn, [noparse][[/noparse]SPSTR 61]    ' capture 58 characters from modem
     GoOn:
    FOR idx = 0 TO 60             ' display capture
      GET idx, test
      DEBUG test
    NEXT
  
    DEBUG CR,LF
   GOTO start
  
  

  
  
  
  As usual I thougt this should be the easy part...
  
  /Rickard
• Jon Williams Posts: 6,491

  2006-01-27 01:45 edited 2006-01-27 01:45

  If you use flow control then you can receive one character at a time and forego SPSTR -- I think that you're going to want that in both directions to get this to work. I suspect the modem is responding before the Stamp is ready with SERIN. You may also need a pull-up or pull-down on the CTS pin (from the Stamp) so that the modem doesn't try to respond while SERIN is being loaded.
  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  Jon Williams
  Applications Engineer, Parallax
• Firestone1 Posts: 5

  2006-01-27 08:42 edited 2006-01-27 08:42

  Ok, I think I understod the first part abaut flowcontrol on serout also.
  
  

  ' {$STAMP BS2px}
  ' {$PBASIC 2.5}
  Rx         CON 1
  Tx         CON 3
  CTS        CON 2
  RTS        CON 15
  test VAR Byte
  idx VAR Byte
  start:
  PAUSE  3000
  
  HIGH CTS
  PAUSE 50
  LOW CTS
  
  SEROUT Tx\RTS, 11505, [noparse][[/noparse]"AT+IPR=?", CR, LF ]
  
  'PAUSE 200 ' wait a while shouldn't be an issue if CTS worked..
  nytt:
  SERIN Rx\CTS, 11505, 2000,GoOn, [noparse][[/noparse]SPSTR 60]    ' capture 58 characters from modem
     GoOn:
    FOR idx = 0 TO 59           ' display capture
      GET idx, test
      DEBUG  test
    NEXT
  
    DEBUG CR,LF
   GOTO start
  
  

  
  
  
  Tried both Low CTS and HIGH CTS and in combination both directions to se if the modem doesn't understand. Nothing worked. Also if I take the comment away for the pause after serout it never works. Shouldn't that work if CTS works as it should. I will take my ocilloscope at work and look whats really happens on the serial port. My guess is that something is broken. I still also have a feeling that it works better when the board have been switched of for a while. I really dont like that kind of symptoms.
  
  I also dont like that the manual states that the modem pauses 100ms before returning response for almost every command.
  
  As you can se I switched to 7E1 to se if that helped, I was told that parity would be more reliable. Yea, right..
  
  Many, many thanks for the help so far. I really apprichiate the rapid response. Sorry for the sometimes bad english.
  
  // Rickard
• Firestone1 Posts: 5

  2006-02-17 20:12 edited 2006-02-17 20:12

  Just wanted to update on this problem.
  
  Problem solved.
  
  As always its some kind of not understanding whats happening. In this case the modem had a "local echo" Doesn't all modems?
  
  When I switched that of, it all started to work correctly. (ATE0)
  
  So now you know.
  
  Best regards
  Rickard