M-bit ring counter/shift register

Thread Starter

dude888

Joined Sep 24, 2007
3
Hi all,

I need an 8-bit shift register which can shift either 1 bit or 5 bits. The register should be able to rotate itself. A ring counter is able to shift 1-bit continuously, but I have no idea how to shift register 5-bit continuously. In the case of 5-bit shift, it should like the following,
bit0->bit5->bit2->bit7....

Does anyone have idea how to implement this shift register?

Thanks
 

thingmaker3

Joined May 16, 2005
5,084
Use on and one quarter 74LS95 chips. Tie Q3 o/p of first chip to Ds of second chip. Tie Q0 o/p of second chip to Ds of first chip. Ignore Q1, 2, and 3 of second chip.
 

Thread Starter

dude888

Joined Sep 24, 2007
3
Perhaps I didn't make myself clear. The 1-bit and 5-bit shift should be implemented with the same chips. Yes, I know that 1-bit and 5-bit shift could be realized with two cascaded 74LS95 chips. But my application is that depending on an detector's output, the shift register should be able to shift either 1-bit or 5-bit continuously. In my opionion, your suggestions need 4 chips, 2chips for 1-bit shift and 2 chips for 5-bit shift. Is it possible to just use 2 chips for both 1-bit and 5-bit shift?
 

Ron H

Joined Apr 14, 2005
7,014
With a shift register, you can only shift one bit per clock cycle. You either have to do multiple cycle shifts, or look into barrel shifters (Google).
Is your process slow enough to allow the use of a microcontroller? That should be simpler.
 
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