serial data

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ish
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serial data

Post by ish » Sat Mar 22, 2003 4:41 am

I have an iei KEYPAD AND AM TRYING TO INTERFACE IT TO MY ccTV SYSTEM THROUGH A bs2. THE IEI KEYPAD HAS A SERIAL OUPUT AND LINE ACTIVE SIGNAL BUT I DONT KNOW THE FORMAT OF THE SERIAL DATA. WHAT SHOULD I USE TO LOOK AT THIS SIGNAL IE :( OSCILLOSCOPE)?

bodgy
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Re: serial data

Post by bodgy » Sat Mar 22, 2003 2:55 pm

An oscilloscope would certainly be the easiest.<p>Apart from anything else you'll need to find the baud rate.<p>You might be able to work out the pattern with a logic probe - though I think you'll soon give up on that idea.<p>Another way if you're uC inclined would be to program the Stamp to record the signal and then play it back out to the debug screen.<p>To do that, you could have the Stamp wait until a start signal, have it start a timer until it detects the next signal. From that it'll be able to work out the baud rate. Then it is just a matter of reading the signal in - possibly to a 30 byte circular buffer as you don't know what you're going to be receiving.<p>The David Benson book serial pic'n has an auto baud rate detecting routine in it as does a uChip application note.<p>Colin
On a clear disk you can seek forever.

ish
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Re: serial data

Post by ish » Sun Mar 23, 2003 5:18 am

THANKS COLIN<p>THAT SOUNDS DO-ABLE

ISH

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