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Guido
03-14-2007, 05:58 AM
Is it possible using Three or four stamps and share the same LCD, using serin and serout?
Thank You
Guido

Mike Green
03-14-2007, 07:03 AM
The easiest way to do this is to use "open" mode for the Baud-mode for the SEROUTs and have a pullup resistor (about 4.7K to 10K) between the LCD serial receive line and +5V. This way, whichever Stamp is transmitting gets control. If more than one Stamp transmits, you get garbage on the LCD. There are many schemes to control which Stamp should transmit. That's a much longer conversation and depends a lot on what you're really trying to do.

Chris Savage
03-16-2007, 11:21 PM
Guido,

You really should have a dedicated controller on the LCD to handle multiple incoming messages since if at any time two BASIC Stamps are talking to it you will lose data. An SX could buffer multiple incoming data streams and prioritize access to the LCD.

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Chris Savage
Parallax Tech Support

Capt. Quirk
03-19-2007, 01:40 AM
You really should have a dedicated controller on the LCD to handle multiple incoming messages since if at any time two BASIC Stamps are talking to it you will lose data. An SX could buffer multiple incoming data streams and prioritize access to the LCD. said...

Are ther any SX/B examples of that somewhere?

Capt. Quirk
03-19-2007, 09:28 PM
Can I use the same idea towards a Parallel LCD using an SX?

Possibly use an 8 bit·data bus with individual RS, RW, E control wires.

Then take it a step further and control RW to pass data from the LCD to the other SX processor without having to use a time consuming·SERIN

Chris Savage
03-20-2007, 04:45 AM
Hello,

There probably isn’t an exact example application or source code but it could be done with the SX rather easily using SX/B. Typically in a system where multiple devices need access to the same hardware you employ a priority encoder. Only one device should have control at any time but having a separate controller moderate that control should only make it that much easier. The other option is to employ logic which would most likely result in poor handling of the data when more than one unit is trying to talk at the same time. Another thing I would consider is handshaking to ensure nothing is lost. Take care.

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Chris Savage
Parallax Tech Support