Assertion to check number of clock pulses

[gv_bing]

No. Let me put it differently
there are two clocks – clk and sck

1. cs_n is a synchronous signal clocked at the posedge of clk
2. cs_n goes low
3. count sck for 16 cycles
4. cs_n goes high

note that when cs_n is high sck is always 0