Serial Port Standard question

nondem

I'm finding that the Board of Education's Serial port(not the USB version) doesn't adhere to the RS-232 standard. In fact - it appears most gadgets don't.

My Bluetooth to DB9 serial adapter sure does and won't work with the BOE - at least not without some effort. I can jumper PINS and get it to work but I have to get the bluetooth connection going BEFORE I plug the adapter into the BOE.

I'm thinking I might be able to wire my own DB9 connector to the BOE and possibly get it to work with my adapter reliably. Maybe·with some minor circuit construction to get all the pins happy.

Can someone confirm this is possible?

Mike Green

The BOE's serial port does not quite adhere to the RS-232 standard as you've noticed, but it does work with most RS-232 serial ports.

The problem you're getting into has little to do with RS-232 and mostly has to do with timing. The Stamp programming process (and the programming process for other Parallax controllers) is timing sensitive and wireless serial adapters just are not fast enough to satisfy the requirements of the downloading process. You can use the programming serial port for data transfers between your Stamp programs and a PC for example, but just not for programming downloads.

steve_b

Also remember that you must have the appropriate pins connect on the stamp.
You need to have both RxD and TxD connected as the stamps rs232 circuit steals power from it's RxD line (hope I got that right!).
You also need the ground and I think pin 4 has to be held high (this is the ATN reset pin on the stamp).

Another side affect of the TxD of the stamp is that it echo's on both lines. Your Bluetooth dongle may not like this...

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<FONT>Steve



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Lee Travino after the second time being hit by lightning!