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Hi, I want to design a single ported RAM [Random Access Memory] in matlab. The Memory will have address, Data and Write Enable as a Input Port. Behaviour is if addr>=0 if WE == 1 X(addr) = din; end Dout <= X(addr); end; So I need to define X as a array I've defined as X = zeros(1,128); % assume RAM size is 128 When I compile this code,I get error message as while evaluating expression: Subscript indices must either be real positive integers or logicals Can anyone help me on M script of RAM? Thanks in Advance Sanjay ____________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now http://uk.messenger.yahoo.com/download/index.html |
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Single Port RAM in matlab
Started by ●April 30, 2004
Reply by ●April 30, 20042004-04-30
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Hi Sanjay, In MATLAB, the array indices begin at 1 and not 0. So, change your code accordingly and it should work. Venu ----- Original Message ----- From: Sanjay <> Date: Friday, April 30, 2004 2:46 am Subject: [matlab] Single Port RAM in matlab > Hi, > > I want to design a single ported RAM [Random Access > Memory] in matlab. > > The Memory will have address, Data and Write Enable as > a Input Port. > > Behaviour is > > if addr>=0 > if WE == 1 > X(addr) = din; > end > Dout <= X(addr); > end; > > So I need to define X as a array > I've defined as > X = zeros(1,128); % assume RAM size is 128 > > When I compile this code,I get error message as > > while evaluating expression: Subscript indices must > either be real > positive integers or logicals > > Can anyone help me on M script of RAM? > Thanks in Advance > Sanjay > > > ____________________________________________________________ > Yahoo! Messenger - Communicate instantly..."Ping" > your friends today! Download Messenger Now > http://uk.messenger.yahoo.com/download/index.html > > _____________________________________ > Note: If you do a simple "reply" with your email client, only the > author of this message will receive your answer. You need to do a > "reply all" if you want your answer to be distributed to the > entire group. > > _____________________________________ > About this discussion group: > > To Join: > > To Post: > > To Leave: > > Archives: http://www.yahoogroups.com/group/matlab > > More DSP-Related Groups: http://www.dsprelated.com/groups.php3 > Yahoo! Groups Links > |
Reply by ●May 1, 20042004-05-01
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I suspect the your problem is the first line of code (addr>=0) which makes it possible for addr=0 and X(addr) would be X(0). Vector indeces must be greater than zero. --- Sanjay <> wrote: > Hi, > > I want to design a single ported RAM [Random Access > Memory] in matlab. > > The Memory will have address, Data and Write Enable > as > a Input Port. > > Behaviour is > > if addr>=0 > if WE == 1 > X(addr) = din; > end > Dout <= X(addr); > end; > > So I need to define X as a array > I've defined as > X = zeros(1,128); % assume RAM size is 128 > > When I compile this code,I get error message as > > while evaluating expression: Subscript indices must > either be real > positive integers or logicals > > Can anyone help me on M script of RAM? > Thanks in Advance > Sanjay ____________________________________________________________ > Yahoo! Messenger - Communicate instantly..."Ping" > your friends today! Download Messenger Now > http://uk.messenger.yahoo.com/download/index.html ===== Juan I. Arvelo, Jr., Ph.D. Johns Hopkins University 11100 Johns Hopkins Rd. Laurel, MD 20723 240.228.4293 __________________________________ |
Reply by ●May 3, 20042004-05-03
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Hi, Thank You for quick response. addr > 0 worked. But Now I landed with different issue. My requirement is I need a Read Before write memory. Here is my m code function demux_out=syn_demux_ref(t,addr,din,we) % Persistent variables for memory functions X =(128:1); persistent d0; % Initialize persistent variables if (t==0) X = zeros(128:1); d0 =0; end if (addr > 0) if (we == 1) X(addr) = din; end d0 = X(addr); end demux_out =[d0]; return what happens here is I write first into array and then d0 will read it. But my requrement is read before write, so I expect zeros to be outputted from my array. when I modify my m code as below function demux_out=syn_demux_ref(t,addr,din,we) % Persistent variables for memory functions X =(128:1); persistent d0; % Initialize persistent variables if (t==0) X = zeros(128:1); d0 =0; end if (addr > 0) d0 = X(addr); if (we == 1) X(addr) = din; end end demux_out =[d0]; return It does not work. Matlab gives following error Error in MATLAB Function block 'demux/Demux_ref/MATLAB Fcn' while evaluating expression: Index exceeds matrix dimensions I'm not able to trace where exactly I'm doing mistake. Is there a way I can do Read before write. Thanks Sanjay --- Ahmed El-Saied <> wrote: > This Error results that you may had made an index = > 0 > there is no index 0 in matlab ,,,, begin index from > 1 > X(1) ---> First Element > X(0) ---> Error , There is no index zero > ----- Original Message ----- > From: "Sanjay" <> > To: <> > Sent: Friday, April 30, 2004 11:46 AM > Subject: [matlab] Single Port RAM in matlab > > Hi, > > > > I want to design a single ported RAM [Random > Access > > Memory] in matlab. > > > > The Memory will have address, Data and Write > Enable as > > a Input Port. > > > > Behaviour is > > > > if addr>=0 > > if WE == 1 > > X(addr) = din; > > end > > Dout <= X(addr); > > end; > > > > So I need to define X as a array > > I've defined as > > X = zeros(1,128); % assume RAM size is 128 > > > > When I compile this code,I get error message as > > > > while evaluating expression: Subscript indices > must > > either be real > > positive integers or logicals > > > > Can anyone help me on M script of RAM? > > > > > > Thanks in Advance > > Sanjay > > > > > > > > > > > > > > > > > ____________________________________________________________ > > Yahoo! Messenger - Communicate instantly..."Ping" > > your friends today! Download Messenger Now > > http://uk.messenger.yahoo.com/download/index.html > > > > > > > > _____________________________________ > > Note: If you do a simple "reply" with your email > client, only the author > of this message will receive your answer. You need > to do a "reply all" if > you want your answer to be distributed to the entire > group. > > > > _____________________________________ > > About this discussion group: > > > > To Join: > > > > To Post: > > > > To Leave: > > > > Archives: http://www.yahoogroups.com/group/matlab > > > > More DSP-Related Groups: > http://www.dsprelated.com/groups.php3 > > Yahoo! Groups Links > > > > > > > > > > > > > ____________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now http://uk.messenger.yahoo.com/download/index.html |
Reply by ●May 4, 20042004-05-04
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The matlab statement zeros(128:1); produces an empty array. If you want to initialize a 128 x 1 size array try zeros(128,1); AMK Message: 6 Date: Mon, 3 May 2004 06:15:55 +0100 (BST) From: Sanjay <> Subject: Re: Single Port RAM in matlab Hi, Thank You for quick response. addr > 0 worked. But Now I landed with different issue. My requirement is I need a Read Before write memory. Here is my m code function demux_out=syn_demux_ref(t,addr,din,we) % Persistent variables for memory functions X =(128:1); persistent d0; % Initialize persistent variables if (t==0) X = zeros(128:1); d0 =0; end if (addr > 0) if (we == 1) X(addr) = din; end d0 = X(addr); end demux_out =[d0]; return what happens here is I write first into array and then d0 will read it. But my requrement is read before write, so I expect zeros to be outputted from my array. when I modify my m code as below function demux_out=syn_demux_ref(t,addr,din,we) % Persistent variables for memory functions X =(128:1); persistent d0; % Initialize persistent variables if (t==0) X = zeros(128:1); d0 =0; end if (addr > 0) d0 = X(addr); if (we == 1) X(addr) = din; end end demux_out =[d0]; return It does not work. Matlab gives following error Error in MATLAB Function block 'demux/Demux_ref/MATLAB Fcn' while evaluating expression: Index exceeds matrix dimensions I'm not able to trace where exactly I'm doing mistake. Is there a way I can do Read before write. Thanks Sanjay __________________________________ |
