How to input initial range of weights in the program code

I am using Matlab 2007a for training my FFNN. Codes are attached here. I have got 4 input nodes and 1 output node. I have selected 8 hidden nodes. how to select the initial weight range for each run? otherwise if i have trained a set using lr-0.9, mc-0.9, it will randomly take a series of weights and if i wanted to change mc keeping constant all other parameters, at that time, training will start with some other sets of weights. so i wanted to keep my initial weight values in the range of -0.5 to 0.5 in all the layers. how to incorporate that in the current program. I will really appreciate it if anyone can help me with this issue

net=newff(minmax(A),[4,8,1],{'logsig','logsig','purelin'},'trainlm'); net.performFcn = 'mse'; net=init(net);

net.trainParam.goal = 1e-4; net.trainParam.min_grad = 1e-20; net.trainParam.epochs = 5000; net.trainFcn = 'trainlm' ; net.trainParam.show = inf; net.trainParam.lr = 0.9; net.trainParam.mc = 0.9; net.trainParam.max_fail = 4; net.trainParam.mem_reduc = 1; net.trainParam.min_grad = 1e-10; net.trainParam.mu = 0.001; net.trainParam.mu_dec = 0.1; net.trainParam.mu_inc = 10; net.trainParam.mu_max = 1e10; net.trainParam.time = inf; net=train(net,A,B);

z=sim(net,A);