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View Full Version : Serial to Multiple BS2s via Programming Port?



Ross
12-05-2009, 02:32 AM
Is it possible to command multiple Stamps via their programming ports from a PC's serial port using a daisy chained DB-9 cable? I only need to send data one way (PC-to-BS2s).

Thanks,

Ross

Mike Green
12-05-2009, 02:45 AM
You may be able to do this. It mostly depends on how many Stamps you plan to use. A PC's RS232 port can only supply so much current and each Stamp will take some. It would help to only connect the PC to Stamp transmit line at each Stamp (and ground of course) and leave the Stamp to PC receive lines unconnected. The Stamp to PC transmit circuitry "steals" a little current from the PC to Stamp line and you won't need that.

Ross
12-06-2009, 09:04 PM
Thanks, Mike. I currently have different flavors of the BS2, eight total, driving 384 LEDs in an art project. I'm guessing that eight Stamps would be too much for the PC port. Perhaps I need to build a line driver to go between the PC's serial port and the Stamps that can source more current?

Thanks,

Ross

Unsoundcode
12-06-2009, 09:59 PM
Hi Ross , might be feasable to use·one Stamp as the PC interface passing info to the other eight.

Jeff T.

Ross
12-08-2009, 03:30 AM
Hi Jeff,

So, basically use a Stamp as a line driver to pass on the serial data to the other Stamps' programming ports? Interesting, I might try that!

Thanks!

Ross

Unsoundcode
12-08-2009, 03:58 AM
Hi Ross , I was thinking more·in the line of·the Stamps communicating serially pin to pin rather than using the programming ports that is if·the slaves·have·at least one·I/O pin available·.

That does not rule out the programming ports·, it's a case of whats best with your setup / plan.

Jeff T.

Ross
12-08-2009, 09:26 AM
Ah, okay. The main reason why I was interested in using the programming ports is that all of my I/O pins are tied up with LED duty.

Thanks,

Ross

Unsoundcode
12-08-2009, 08:12 PM
You could still use a master Stamp to route the PC data and use 4 MAX 232 or MAX 323·TTL to RS 232 drivers hooked to the programming ports of the slaves.

There may be other solutions but I think the above·would work nicely, the MAX chips are very straightforward to use and relatively cheap.

Jeff T.·

Ross
12-09-2009, 03:38 AM
Thanks, Jeff! I'll check those out. I might even already have those in my box of ICs. I remember buying TTL to RS232 converters a while back for a project that never got going.

Thanks,

Ross