MATLAB: How to center axis labels in pcolor graph

Question

I have a pcolor "checkerboard plot" , how do I center the axis values to the center of the box (but still on the axis). I am using matlab 2012b.

Heres some code:

figure;
pcolor(1:13,1:5,ones(5,13))
xt = 1:12;
yt = 1:4;
set(gca,'XTick',xt)
set(gca,'YTick',yt)

Answer 1

setting axis x location to origin didnt work for me.

I changed some code and used imagesc instead of pcolor.

c = zeros(5,5);
c(1,1) = 1;
im = imagesc(c);
ax = gca;
ax.XTick = 1:5;
ax.YTick = 1:5;
ax.YDir = 'normal';