| """ |
| A model of the fractional N divider. |
| """ |
| |
| import mash_mod_model |
| |
| class fractional_n_divider_model(): |
| |
| def __init__(self, integer_width, modulus_width, order, divide_value=1): |
| """ |
| Instatiate the model object |
| """ |
| |
| # store the modulator parameters |
| self.integer_width = integer_width |
| self.modulus_width = modulus_width |
| self.order = order |
| self.divide_value = divide_value |
| |
| # create internal state variables |
| self.count = 0 |
| self.mash_output = 0 |
| |
| # create the mash model object |
| self.mash_mod_obj = mash_mod_model.mash_mod_model(self.modulus_width, self.order) |
| |
| |
| def reset(self): |
| """ |
| Reset the internal state of the modulator |
| """ |
| |
| # reset internal state variables |
| self.count = 0 |
| self.mash_output = 0 |
| self.mash_mod_obj.reset() |
| |
| |
| def set_divide_value(self, divide_value): |
| """ |
| Set a new divide value |
| """ |
| |
| # reset internal state variables |
| self.divide_value = divide_value |
| |
| |
| def update(self): |
| """ |
| Update the state of the modulator with new data |
| """ |
| |
| # combine to find a new count target |
| integer_component = int(self.divide_value) |
| count_target = integer_component + self.mash_output |
| |
| # print('count_target', count_target, 'count', self.count) |
| |
| if self.count == count_target: |
| |
| # pull out the fractioanal component |
| fractional_component = self.divide_value % 1 |
| |
| # find out the next mash modulated value |
| self.mash_output = self.mash_mod_obj.update(fractional_component) |
| |
| # reset and siganl a rising edge |
| self.count = 0 |
| output_data = 1 |
| |
| else: |
| |
| self.count += 1 |
| output_data = 0 |
| |
| return output_data |
