SPI Shift Register

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Looking for a shift register for both serial in parallel out and parallel in serial out for use on SPI bus. Any suggestions are appreciated.

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HC595, HC164, HC165

Stealing Proteus doesn't make you an engineer.

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anything that is bidirectional?

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Looking more into whats available, is there any difference between a port expander and an actual shift register? Seems like the port expander will do exactly what I need and a shift register will do the job also but not as compactly.

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HC299

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With a bidirectional device, you will have to provide all the different strobes, latch-shifteregister-to-out, latch-in-to-shiftregister, etc. It is then no longer real SPI which "should" take only a clock, an enable, MOSI, and MISO.

How about using a Tiny? Then you could do it with a 1 byte "command" and a 1 byte data, read or write, depending on the command. Would really reduce the number of parallel control lines needed.

Jim

 

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new2use wrote:
anything that is bidirectional?
How often do you plan to amend the requirements?

Stealing Proteus doesn't make you an engineer.

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Never once they are set as input or output they will not change

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Microchip MCP23S17 and MCP23S08 sound like they might be what you're looking for. The'S17 is a 16 bit I/O port, and the 'S08 is an 8 bit port. Both are bidirectional and use only the SPI interface. There are also versions of both chips available using I2C if you happen to find that useful.

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This should give you a broad selection:

http://search.digikey.com/script...