Need help with programing a 10 segment display
Dwarg91
Posts: 2
Hey does anyone here know how to program a homework board to use a ten segment bar display
it came from radio shack catalouge #276-081
it came from radio shack catalouge #276-081
Comments
i lost mine because it was on the BACK of the packaging
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When the blue smoke comes out of a Basic Stamp... You know that you did something wrong... -- Matthew
Post Edited (Matthew Burmeister) : 2/3/2008 12:50:14 PM GMT
The easiest way to·utilize it is with an LED Bar Dot Driver chip. This chip takes care of all the individual LED units, and leaves you with only the control function to deal with. You start with the digital representation of a number, and the appropriate number of LED's will light up on the display. I do hope that's what you were trying to accomplish!
Somewhat unfortunately, these are analog devices which accept only a 0-5 VDC signal source, and that will have to be developed external to the PBASIC Stamp. I suppose you could fool around with the PWM command, but I suspect you might not get the fineness of voltage selection that you will with a DAC (digital to analog converter) chip. I have attached a copy of a readily available LED BAR DOT Display chip (LM-3914) made by National Semiconductor. If you wish, you may even be able to aquire a sample from them.
The DAC I have chosen is one of many that might be used. You will also find attached, a datasheet for the Maxim MAX-550A, an 8-bit Serial DAC, in PDIP format. You will send·the digital·number from the Stamp·to the DAC using the SHIFTOUT command, and the appropriate analog voltage (0-5 VDC) will appear at the output terminals of the DAC. Now you have a digital device (the Stamp) producing an analog output (via the DAC).
Here is how it all fits together. The synchronous serial, digital output of the PBASIC Stamp will be the input to the MAX550A serial DAC. The output of the serial DAC will be the input to the LED Bar Dot Driver chip. The output of the LED Bar Dot Driver chip will be the input to your 10-segment LED display. In other words, one feeds the other, right on down the line.
One last bit of information which I found on the Radio Shack web site. That LED Display requires 2.0 VDC to drive the LED's,·for it to operate properly.
Regards,
Bruce Bates
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There is no pleasure in having nothing to do;
the fun is in having lots to do, and not doing it!
Are samples free?
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When the blue smoke comes out of a Basic Stamp... You know that you did something wrong... -- Matthew
Yes, samples of chips and semiconductors are generally free. Each specific manufacturers web site will indicate their samples policy. Maxim is noted for their liberal samples policy, and so too Allegro Micro, and a few others that are not coming to mind at this moment.
Even if there is no stated policy, it can not hurt to ask. The worst they can say is "Sorry, we don't offer samples".
Regards,
Bruce Bates
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There is no pleasure in having nothing to do;
the fun is in having lots to do, and not doing it!