Basic Stamp BS2p and Agilent Waveform Generator

zacharypch ~!at!~ gmail ~!dot!~ com · 2006-06-02 18:21

Hi,

I am trying to get my basic stamp to communicate with an Agilent 33250A Arbitrary Waveform Generator via RS-232...I am not trying to do anything specific with the generator, I just want to figure out how to do serial communication. The command set the generator offers seems to be very similar to other devices, however I have not been able to figure out how to do serial communication on anything yet. Here is a subroutine I am trying to make work now:

ResetValueInt    CON     2
ResetValueDec    CON     5

COMOutput CON   16
COMInput  CON   16
COMBaud CON     110
FUNC_GEN_XON               CON     $11
FUNC_GEN_XOFF              CON     $13

ResetVoltage:
  SEROUT COMOutput, COMBaud, [noparse][[/noparse]HEX FUNC_GEN_XON]
  PAUSE 50

  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"output:state off", CR]

  PAUSE 50
  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"output:sync off", CR]
  PAUSE 50

  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"func square", CR]
  PAUSE 50
  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"frequency 1", CR]
  PAUSE 50
  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"volt:high 1", CR]
  PAUSE 50
  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"volt:offset 0", CR]
 ' SEROUT COMOutput, COMBaud, [noparse][[/noparse]"func:square:", CR]
  PAUSE 50

  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"burst:ncycles 1", CR]
  PAUSE 50

  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"output:state on", CR]
  PAUSE 50

  SEROUT COMOutput, COMBaud, [noparse][[/noparse]"output:sync on", CR]

  PAUSE 50
  SEROUT COMOutput, COMBaud, [noparse][[/noparse]HEX FUNC_GEN_XOFF]

  RETURN

Currently, the device reports input buffer overrun and packet framing errors, or otherwise fails to effect any outcome whatsoever. The function generator is connected to the BS2P24/40 via RS-232 crossover.

Thanks for the help.

PJAllen · 2006-06-02 18:44

Framing error usually results from parity error, possibly bps or Stop Bit.· Is this Agilent unit 8-N-1?··The STAMPs can only do 8-N-1 or 7-E-1 (no 8-N-2, 7-N-1, 8-E-1,·&c.)

Bean · 2006-06-02 18:50

Have you tried both inverted and true serial modes ?
That can cause framing errors too.
Bean.

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Bruce Bates · 2006-06-02 19:01

Zachary -

It would appear from the Agilent documentation that the default baud rate is 57.6 KBPS, unless you have changed it. Presuming you have, I suspct you now need to implement flow control for this to work properly. Your program is presently specifying a baud rate of 19.2 KBPS.

Just as a matter of reference, the default parameters for this generator are:

57.6 KBPS, 8, N, 1 start, 1 stop, DTR/DSR enabled

Since the units are not synched without the flow control, I suspect that's where these framing errors and/or data over-runs are coming from.

Just as a matter of information, with flow control enabled, the BS-2p is speed-limited to 19.2 KBPS. The PBASIC Manual or the PBASIC Help File will show you what you need to do to enable flow control.

Regards,

Bruce Bates

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zacharypch ~!at!~ gmail ~!dot!~ com · 2006-06-02 19:03

PJ:
I dont think I a m familiar with your notation. The user manual for this device shows that it can do even or odd parity, as:
Start | 7 bits | Parity bit | stop bit
Or with no parity as:
Start | 8 bits | stop bit

I do not know what to do with the start and stop bits at this time, but if I am trying to send ascii, then that is 8 bits per char, does this mean that I have to do something smart with the bits before and after? Or is there some way I can tell the stamp to do it right?

Bean:
I don't think I know what those are...

zacharypch ~!at!~ gmail ~!dot!~ com · 2006-06-02 19:12

Ok, well I see that I can specify a pin to use to monitor flow control, but what should it be wired to?

Bruce Bates · 2006-06-02 19:36

Zachary -

As I mentioned a few moments ago, the PBASIC Manual or the PBASIC Help File will show you what you need to do to enable flow control. There is a standard RS-232 connector on the back of the generator, so everything should fall into place once you read the instructions, as the wiring set-up for flow control is also indicated in those instructions.

Regards,

Bruce Bates

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zacharypch ~!at!~ gmail ~!dot!~ com · 2006-06-02 19:40

Ok, well I think my problem is that I don't know how to access the ATN pin from the basic stamp on my bs2p24/40 demo board. Ill find it though, thanks for your help.

RGuyser · 2006-06-03 05:30

would a max232 chip help him?

Basic Stamp BS2p and Agilent Waveform Generator

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