METHOD AND APPARATUS TO AUTOMATICALLY SCALE DLL CODE FOR USE WITH SLAVE DLL OPERATING AT A DIFFERENT FREQUENCY THAN A MASTER DLL

摘要

A method and apparatus for scaling a DLL code for a slave DLL operating at a different frequency than a master DLL is disclosed. An apparatus includes a master DLL coupled to receive a first clock signal and a group of series-coupled slave DLLs coupled to receive a second clock signal. The master DLL may provide a specified fraction of a cycle of the first clock signal. Scaling circuitry coupled between the master DLL and the group of slave DLLs may determine a ratio of frequencies of the first clock signal to the second clock signal. Based on the ratio and a delay code from the first DLL, the scaling circuitry may generate an adjusted delay code received by the group of slave DLLs to set a delay for the second clock signal to the specified fraction.