HOW CAN I DESING AN ALU?

Have you looked at the 74181 datasheet? I found this amusing

I'm having trouble with the "most little parts" part of that. Do you mean:

(A) A low number of parts of any kind.

(B) A low number of small parts.

(C) It must use diodes and transistors and not complete ICs and keep the number of them low.

For (A) I'd suggest a CPLD programmed to be an ALU.

For (B) I'd suggest the 74HC181 (IIRC)

For (C) I'd suggest finding out what you can but the cheapest first.

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kensmith@rahul.net   forging knowledge

Then you first have to specify the requirements. Minimum parts are achieved with minimum bit-width, in this case 2 bits, and by having a minimum number of operations, here add & sub, that makes an operation selector with one bit.

Rene

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Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

Si usted necesita esta mucha ayuda en este tiempo en sus clases, usted no ha estado aprendiendo claramente las lecciones. Él si todos están en sus libros de textos y notas de la conferencia. Un subtractor es simplemente una serpiente[1] con una inversión del dos-complemento del subtrahend. End-around lleve, por supuesto, es opcional. ¿Cómo difícilmente puede estar?

Buena Suerte! Rich

[1] Oopps! This is how google translated "adder." Heh! So much for artificial intelligence! >:->

DooD! They're doing a barrel shifter in 7408's! Geez, why not ask the guy to build a PDP-11?

;-P

Cheers! Rich

Try this: "VHDL for Programmable Logic" written by Kevin Skahill of Cypress Semiconductor pages 293- 326 A case of the 2901 bit slice chip

Good luck, Dave

I would base you ALU on an FPGA, e.g. Xilinx, Altera or Lattice. For code examples in Verilog and VHDL, take a look at ...

There are several CPU designs and most if (not all) are GPL :-)

Mike.

thank you, but 74HC181 is an 4-bits ALU, but I need a 2-bit ALU can you help me? Andrew Holme ha escrito:

Off the top of my head...

1) Half-a-181 2) PROM (of some sort) 3) FPGA or CPLDish thing

A two-bits won't cut it these days.

-- Keith

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