CDR Frequency Library

The freq_utils package include two functions that are used by the top level project file.

Freq_to_m

The freq_to_m function is used in order to transform the g_freq_out top level generic into a jump size value for the NCO.

The function’s inputs are:

• The system clock frequency, given by the g_freq_in top level generic, real
• The NCO expected nominal frequency, given by the g_freq_out top level generic, real
• The multiplication factor, given by the g_multiplication_factor top level generic, positive
• The NCO number of bits, given by the g_number_of_bits top level generic, positive

The function’s declaration is freq_to_m(g_freq_in, g_freq_out, g_multiplication_factor, g_number_of_bits) and returns a real

Freq_to_mmcm

The freq_to_mmcm function is used by the MMCM to generate the clkfbout_mult_f and clkin1_period generics in order to keep the VCO frequency at 1 GHz

The function’s input is:

• The NCO expected nominal frequency, given by the g_freq_out top level generic, real

The function’s declaration is freq_to_mmmc(g_freq_out) and returns a real