XOR gate using backpropagation.not getting correct output

this is the complete code no matter how many iterations i take, the weights are not converging and the output is not showing correct answers

input=[0 0 1 1 0 1 0 1];

output=[0 1 1 0];

bias = [-1 -1 -1];

coeff = 0.2;

weights=randn(3,3);

for i = 1:8000

for j=1:4

    I=input(:,j);
    q=output(1,j);

      H1 = (-1)*weights(1,1)+I(1,1)*weights(1,2)+I(2,1)*weights(2,2);
      x1 = logsig(H1);

      H2 = (-1)*weights(2,1)+I(1,1)*weights(1,3)+I(2,1)*weights(2,3);
      x2 = logsig(H2);

      x3_1 = (-1)*weights(3,1)+x1*weights(3,2)+x2*weights(3,3);
      out= logsig(x3_1);

      err=q-out;
      e=.5*err^2;

      delta3_1 = out*(1-out)*(q-out);     
      delta2_1 = x1*(1-x1)*weights(3,2)*delta3_1;
      delta2_2 = x2*(1-x2)*weights(3,3)*delta3_1;

            weights(1,1) = weights(1,1) + (coeff*(-1)*delta2_1);

            weights(2,1) = weights(2,1) + (coeff*(-1)*delta2_2);

            weights(3,1) = weights(3,1) + (coeff*(-1)*delta3_1);

            weights(1,2) = weights(1,2)+ (coeff*I(1,1)*delta2_1);

            weights(2,2) = weights(2,2)+ (coeff*I(2,1)*delta2_1);

            weights(3,2) = weights(3,2)+ (coeff*x1*delta3_1);

            weights(1,3) = weights(1,3) + (coeff*I(1,1)*delta2_2);

            weights(2,3) = weights(2,3) + (coeff*I(2,1)*delta2_2);

            weights(3,3) = weights(3,3) + (coeff*x2*delta3_1);

 end

end

q1=logsig((0*weights(1,2))+(0*weights(2,2))+weights(1,1));

q2=logsig((0*weights(1,3))+(0*weights(2,3))+weights(2,1));

q3=logsig((q1*weights(3,2))+(q2*weights(3,3))+weights(3,1))