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HP50g serial communication with 3rd party device
07-26-2015, 02:44 PM
Post: #7
RE: HP50g serial communication with 3rd party device
(07-26-2015 12:28 PM)Marakasmalan Wrote:  OK, so I tried it, but no success really.

After each command (SMIT, SRECV, BUFLEN), it returns a "1" - does that indicate an error occurred or does that indicate success?

The return information is not the same after repeating the same command to the device, and furthermore it is "garbage", unintelligable an sometimes up to three characters of sensible information.

What I do not know is what Xlat need to be set to, though I played around with different settings and also dit try different values for wait, from one up to seven.

Unfortunately I do not have a 48 that I could try the same with.

ANy ideas?

What are you communicating with? Are you sure the signal from the device is at the correct voltage levels for RS232? Did you try removing the wait command? Instead of using BUFLEN you may want to directly enter in the number of characters expected in the response (see below)

BUFLEN DROP SRECV DROP2 @Clears Buffer of any old data
"Command" XMIT DROP @Sends "Command" string to serial device
10 SRECV DROP @Receives data via serial until 10 characters are received or STIME has elapsed with no response, adjust the number 10 to correspond the expected length of the response from the serial device.

Think you meant XMIT not SMIT. 1 indicates success, but with XMIT this means only that the calculator successfully sent the command doesn't indicate it was successfully received by the other device.

BUFLEN returns the number of characters in the HP48 IO Buffer so this may not correspond to your expected response length if the entire response doesn't fit in the buffer or hasn't been fully sent yet.

You should also turn off the clock display. The ticking clock may interrupt the transfer and corrupt data.

If none of this works you may want to verify whether you can control the device via HyperTerminal or some other program to make sure the problem isn't on the device end.

Good luck let us know how it goes
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RE: HP50g serial communication with 3rd party device - snrowe - 07-26-2015 02:44 PM

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