BS2sx not detected !

Boris

Hello,
I am working on a project that requires BS2sx to be connected to a rs232 Baud Rater converter (http://www.bb-elec.com/product.asp?SKU=232BRC). The BS2sx OEM module is connected via the on-board 9pin RS232 port directly to the 9pin port on the baud rate converter. The entire assembly is placed in a project box with some other components. The project is still in development stage and BS will have to be reprogrammed. I soldered 9 wires to the 9pin connector on the Baud Rate Converter (the same connector that the BS is attached to). And those 9 wires terminate with another 9pin RS232 port. The idea was to use that wire, connected to PC, to program the BS w/out removing it from the project box, or unhooking it from BRT board. Unfortunately, when i pluged that wire into the PC, and ran Basic Stamp editor 2.1 it said "Stamp Not Found", i have checked and double checked the wiring, all the wire go strraight through no problems... I even turned off the power to the BRT. Can BRT be causing some problems? What does BS Editor do to check if the stamp is present or not?

Thank you,

Boris.

Jon Williams

When the editor "looks" for a BASIC Stamp module, a reset is activated by blipping the DTR (ATN) line -- this forces the BASIC Stamp to reset and output its type. Your BRB is probably interfering with the reset process.

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

Jonb

The converter may be acting as a "null modem" cable might. Why are you using that thing?

Boris

But BRT is essentially connected in parallel to the BS

_______ to BS
Wires from PC<_______ to BRT

You think it might still cause interference. DTR is PIN4 on DB9 right?

"The converter may be acting as a "null modem" cable might. Why are you using that thing? "
what do you mean by "null modem"
I have to use it because the project needs to communicate with a device that uses 9600bps and differnt partiy, BS2sx does not support that comunication mode.

Jonb

Yes pin4, I always refer to the schematic for the SX module, at the bottom:
But pin4 on the straight through 9 pin serial cable(as opposed to null modem cable)·coming from the PC.
http://www.parallax.com/dl/docs/prod/schem/bs2sxrevd.pdf

When programming the BS from a PC, a null modem cable wont work. The wires get switched around...

In a perfect world, all serial ports on every computer would be DTE devices with 25-pin male "D" connectors. All other devices would be DCE devices with 25-pin female connectors. This would allow you to use a cable in which each pin on one end of the cable is connected to the same pin on the other end. Unfortunately, we don't live in a perfect world. Serial ports use both 9 and 25 pins, many devices can be configured as either DTE or DCE, and - as in the case of many data collection devices - may use completely non-standard or proprietary pin-outs. Because of this lack of standardization, special cables called null modem cables, gender changers and custom made cables are often required.

A Null Modem cable or Null Modem adapter simply crosses the receive and transmit lines so that transmit on one end is connected to receive on the other end and vice versa. In addition to transmit and receive, DTR & DSR, as well as RTS & CTS are also crossed in a Null Modem connection.

Taken from http://www.taltech.com/TALtech_web/resources/intro-sc.html#cablenulls

This makes me think of the guys on the street that place a ball under a cup and switch cups around.
You've got the pinout on the modem, the cable to the converter, the converter itself, then the cable to the stamp. Wheres the ball?

But i'd listen to Jon Williams, he knows best..




Post Edited (Jonb) : 1/24/2005 9:57:25 PM GMT