Increase Basic Stamp Input/Output Pin

efly

Dear all,
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I would like to check if BS2 can increase the input/output pin from existing 16 pins (P0 to P15) to 32 or MORE as I want to flash LED light which may need to turn on and off at the same time with individual mode.
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Many thanks.····
Efly

Zoot

If you need more output pins, you can use a shift register like the 74HC595 -- this lets you control the output state of 8 pins using only 3 pins on the Stamp (see SHIFTOUT in the Stamp manual for examples). You can "cascade" additional 74HC595's if you need even more pins. Do a search at the forums and you will turn up tons of sample code that use this chip.

You could also use program an SX28 to accept commands via serial. This would only require 1 pin on your Stamp and would give up to 19 extra pins to use on the SX28. You would also be very flexible because you could program the pins to do whatever you want; however this would require purchasing an SX programming key and would take some more homework.

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When the going gets weird, the weird turn pro. -- HST

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efly

Thanks!···
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Regarding the 74HC595 shift register, may I know where can I buy it?
In fact I have visited the Parallax page as there is an item call “74HC595 Serial to Parallel”, is this similar product since it is no detail mention how it work on the page…
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Following is the homepage:-
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http://www.parallax.com/Store/Components/IntegratedCircuits/tabid/154/CategoryID/31/List/0/SortField/0/Level/a/ProductID/229/Default.aspx
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Efly
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Zoot

Yes that's the chip; you can buy it from Parallax, Digikey, Mouser and just about anywhere that sells IC chips.

You communicate with the '595 via synchronous serial (clock, data, enable) -- 3 pins. Look in the Stamp manual under SHIFTOUT and you will find example code (read up before you buy!).

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When the going gets weird, the weird turn pro. -- HST

1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php