Parallax Professional Development Board & MAX232E

gadget

Received the PDB a couple of days ago, and have to say this is great so far. Where I have managed to test most of the functions have hit a snag on using the MAX232.· Can anyone share a short example for using the MAX with a BS2 just to confirm it’s working with the PDB? ·Thanks.
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Cheers, Michael

LoopyByteloose

The BasicStamps all have a programing interface through their own [noparse][[/noparse]on the Stamp] RS-232 interface. So for the ATN pin and that RX and TX, you don't need the MAX232. It may not be as powerful as the MAX232 for long cables.

If you add another serial port [noparse][[/noparse]let's say you have a Serial LCD that uses RS-232], you can configure the second serial port to run through the MAX232.

The signals to/from the BS-2 are TTL [noparse][[/noparse]which are 0 V and +5 V] while the signals to/from the RS-232 side of the MAX232 are +10 Vand -10 V]. This higher voltage allow you to have long wires. Also, the MAX232 is set up for two recieve and two transmit lines. If you want, you can add hardware control on PINs 7 and 8 of you DB-9 connect for a 4-wire interface. Alternatively, you can have two separate 2-wire RS-232 ports.

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G. Herzog in Taiwan

steve_b

What's your code gadget?
Just note that when you're talking to the max232's TTL lines...you should be in TRUE baudmode...whereas you would be in INVERTED baudmode if you were listening to rs232 lines (don't forget your inline resistor for safety -- 220ohm I believe)

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Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

Jon Williams

Here's the code and schematic for a project that uses that port in StampWorks 2.0.

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Jon Williams
Applications Engineer, Parallax

gadget

Would like to thank you all for the input. Kramer/Steve your input will help with future plans and Jon this is perfect to work with the PDB will just have to get my hands on a DS1620. Again, thank you very much. Cheers, Michael

Jon Williams

You can still run that program without the DS1620 -- you'll just get bogus values back if you ask for temperature. The point is that you can learn to connect and use the DCE serial port on the PDB.

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Jon Williams
Applications Engineer, Parallax

gadget

Jon, Cool, Thanks.