Serial Pole Display problems

JimAvanti

I am having major problems trying to get a pole display to accept text from my stamp.· I tried a DP2000 display with no luck.· I just purchased a DP2100 and still get nothing.· When I connect the stamp to hyperterminal I get all the correct information.· When I connect the Display to the computer I can read everything I type on the display.· The output from the stamp to the display gets nothing at all.· The displays are 9600,N,8,1.· I am using the command SEROUT tx, 84, 5, [noparse][[/noparse]char]· (TX is Pin 15).· I also tried using hanshaking, and I tried tying serial port pins 1,4,6 together and 7,8 together.· I am using the MAX232E built onto the professional Development·board.· Can anyone help me?· Has anyone had any success using any of these displays?

Thanks.
Jim

Jon Williams

Perhaps you should provide a link to the tech docs for your display -- if you make people go hunting... they won't.

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Jon Williams
Applications Engineer, Parallax

JimAvanti

Sorry,

The pole display is from Posiflex.

http://www.posiflex.com.tw/object/Manuals/User/UMPD2X00B4.pdf

Jon Williams

That document gives no protocol information....

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Jon Williams
Applications Engineer, Parallax

Paul Baker

It appears there are 4 emulation modes, and suggests going to thier site for commands. There is nowhere on the site that I can find such commands, but if you can find the commands for a particular pole display emulation (by going to the other 4 manufacturer's sites) I would use that and set the display to emulate that mode.

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·1+1=10

JimAvanti

The 4 emulation modes really are useless... They are Futaba, Noritake (default), Aedx (Which is all commands and passthru), and Epson mode (Which just uses the Epson fonts.· They are selected with dip switches.· The stuff that really matters is that it is 9600,N,8,1 with no handshake.· When I connect the display to my com port on the computer I can type in Hyperterminal and the display accepts the text o.k.· When I connect the display to the Max232e port of the basic stamp it displays nothing.· I have a com port snooping cable (It has a resistor and diode to see what is going on during communication between two devices... the stamp and the display).· The computer shows the characters from the stamp o.k., but the display won't show anything.· I am stumped...· It has to be some electronic/timing or voltage problem coming from the proto board's serial circuit, because the display works from other devices set to 9600,N,8,1.·

I was hoping someone out there has used one of these displays and got it going.· Maybe I need to make a different serial circuit using somthing other than a Max232e chip...?

Thanks,

Jim

Paul Baker said...
It appears there are 4 emulation modes, and suggests going to thier site for commands. There is nowhere on the site that I can find such commands, but if you can find the commands for a particular pole display emulation (by going to the other 4 manufacturer's sites) I would use that and set the display to emulate that mode.

JimAvanti

The protocal is 9600,N,8,1 with no handshaking.· The emulation modes on the display don't really matter... I tried all 4, but they should all work.· When the display is plugged into my computer running hyper term @ 9600/N/8/1 it works fine...· Just when it is plugged into the Max232E circiut of the development board do I get no response.

Jim

Jon Williams (Parallax) said...
That document gives no protocol information....

Jeff Dege

If you send data to the pole from Hyperterminal on your PC, it displays

If you send data to the pole from your MAX232E circuit to the pole, it does not.

Have you tried sending data to Hyperterminal on your PC from your MAX232E circuit?

Steel

Are you seeing correct RS232 Voltage levels coming out of the Max233 Chip?

Verify that PIN15 is truely outputing the 5VTTL signal, then check the output on the Max233 to verify that it is sending the RS232 signal.

JimAvanti

Yes, that works fine.· Also, I have a Serial sniffing cable that will capture the two-way communications between two devices (The MAX232E circuit and the pole display) and display the results in a terminal program.· The sniffer shows the data, but the display shows nothing.· very strange.

Jeff Dege said...
If you send data to the pole from Hyperterminal on your PC, it displays

If you send data to the pole from your MAX232E circuit to the pole, it does not.

Have you tried sending data to Hyperterminal on your PC from your MAX232E circuit?

Jon Williams

Assuming the hardware connections on the PDB are correct (easily verified by connecting that port to a terminal running at the same baud), make sure you've got the correct baudmode value for the Stamp module you're using -- this is a frequent stumbling point.· I use the attached template as it contains the right values for popular baud rates.

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Jon Williams
Applications Engineer, Parallax

JimAvanti

It shows 5v.· The same program outputs o.k. to my terminal software... just not the display (And I have two displays I am tring to get to work).·

Steel said...
Are you seeing correct RS232 Voltage levels coming out of the Max233 Chip?

Verify that PIN15 is truely outputing the 5VTTL signal, then check the output on the Max233 to verify that it is sending the RS232 signal.

Jon Williams

Can you post your test program... maybe there's something you're taking for granted.

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Jon Williams
Applications Engineer, Parallax

JimAvanti

I just added a Dallas DS275 chip to the circuit instead of using the MAX232 built into the development board and the display is now working correctly.· There has to be something very picky about the display or something non-standard with the Max232 circuit, but at least I got it working!· Thanks,



Jim

Jon Williams (Parallax) said...
Can you post your test program... maybe there's something you're taking for granted.