Verilog code errors???

First problem, you are trying to uses assign statements for registers.

Better to uses:

CS_1 and CS_2 would have to be defined as registers.

always @(posedge Clk26mhz)

begin

CS_1 <= CS1reg;

CS_2 <= CS2reg;

end

I'm assuming on your# 2, you are trying to do a test bench reset strobe where rstb = 0 for 500 ticks then 1.

This should be done in an initial block. and rstb defined as a register.

initial

begin

rstb = 1'b0;

# 500

rstb = 1'b1;

end