How to iterate across a specific diagonal?

Hello, I am a beginner to matlab and wondering if anyone can help me with this specific problem. Here is my code

N1=2;

N2=2;

nband=1;

n=(N1*N2)*2*nband;

t=4;

HM = zeros(n);

% upper t diagonal

for ii = (N1*N2*nband):n

HM(ii,n+1-ii) = t

end

HM

% end

What I am trying to do is get a diagonal of 4's or the t variable across the the half diagonal of the matrix. Here is an image for reference. It must work for all values of N1 and N2. For example, if N1 =3, N2=2, then I would like the 8th diagonal to be iterated through the t variable. It is basically half of the n dimension. I am stuck. Any help is appreciated if possible! Thank you so much

[Stephen23]

Why use a loop?

fliplr(diag(4*ones(1,4),4))

ans = 8×8

0 0 0 4 0 0 0 0 0 0 4 0 0 0 0 0 0 4 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Answer 1

[Voss]

N1=2;
N2=2;
nband=1;
n=(N1*N2)*2*nband;
t=4;
HM = zeros(n);
% upper t diagonal
for ii = 1:(N1*N2*nband)
    HM(ii,(N1*N2*nband)+1-ii) = t;
end
HM

HM = 8×8

0 0 0 4 0 0 0 0 0 0 4 0 0 0 0 0 0 4 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

[Karen Smith]

Thank you so much!