DEF_RELAX
relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;