How to shrink time scale for discrete signal?

%if 
bits = [1,0,1,1,0,0,0,1];
% Mapping
for a=1:length(bits)
  if bits(a) == 1
      bit(a) = 5;
  else
      bit(a) = -5;
  end
end
i = 1;
t = 0:0.01:length(bits);
for b=1:length(t)
  if t(b) <= i
      y(b) = bit(i);
  else 
      y(b) = bit(i);
      i = i+1;
  end
end
plot(t,y);
end

I am trying to change the duration of 1 bit from 1s to 1us and the scale would be 0 to 8us with a step of 1e-8. I am getting an error if I do it using this method and if I specify my own time scale it will only print the first value that goes from 0 to 1. Any ideas???