Re: RAM64

Posted by cadet1620 on Jul 05, 2016; 3:57pm
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/RAM64-tp4025254p4030002.html

Desmond.Song wrote

Hi, I'm also finished RAM64, but I have a puzzled  about the last sentence of code,

"Mux8Way16(a=outa,b=outb,c=outc,d=outd,e=oute,f=outf,g=outg,h=outh,sel=address[3..5],out=out);"
That is 'address[3..5]', because I start using 'address[0..2]'.

When  I running  RAM64.hdl, it throw an error. so I tried to modify '[3..5]' to '[0..2]' , unbelievably, RAM64.hdl  was running well.

You can use any 3 of the address bits in the output multiplexor, but you need to use the same 3 bits in the demultiplexor that handles 'load'. The 3 bits that are not used in the mux and demux must be used for the addresses for the RAM8s.

--Mark