The Design And Verification Of A SD Card Controller Supporting SD3.0 Protocol

With the continuous development of electronic products,the demand for storage equipment is growing,large capacity,miniaturization,high performance are the first factors of selecting a storage equipment.Because of its small size,fast transmission,low price SD card has become the main storage media expansion of storage equipment in electronic products.In order to meet a So C in the SD card storage data high-speed access requirements,this paper designed a SD card controller IP core and verified its function.This design of IP core is based on SD3.0 protocol,compatible SD 3.0 and below,support UHS-I card high-speed transmission and built-in DMA transfer function.This paper first introduced the protocol of SD3.0,according to the project needs to determine the controller specifications,then proposed the controller design.The controller structure is divided by the top-down design method and the functions of all the components of the controller are determined.The SD card controller is divided into bus interface unit,card interface unit,clock domain synchronization logic unit and RAM interface unit.Bus interface unit is responsible for communicating with the CPU and providing the controller with an external bus interface,an internal register,a DMA and a clock tuning module;the card interface unit is responsible for communicating with the controller with the external SD card,providing the controller with command sending,responsereceiving,data transfer,CRC check function and provide working clock for SD card.The clock domain synchronization logic unit provides reliable clock domain synchronization for all control paths within the SD card controller.The RAM interface unit is responsible for the internal data cache control of the controller.This paper focuses on the detailed design of the clocktuning moduleand the DMA module in the bus interface unit.The clocktuning module is designed to support the UHS-I card,providing the controller with a UHS-I card to select the best sampling clock before transferring data at high frequencies.This module is implemented by a clock sampling algorithm to achieve the clocktuning function,and provids a safe and reliable best sampling clockfor the SD card controller.DMA module provides a new DMA algorithmfor this SD card controller,making the data transmission more efficient.The function of controller is verified after its RTLcompleted.Designed the required model and built the module-level verification environment,to complete the module-level function verification,access to 100% code coverage.and then use the verification environment which based on So C platform completed the system-level function verification of the controller.Verification results show that this SD card controller function meets SD3.0 protocol,read and write function is right,DMA mode transmission is right,the clock tuning function is right,support UHS-I card speed mode,and it is stable and reliable.