Reconfigurable chip design of bidirectional access controller to the SD card using FPGA

Embedded systems often process information in very different ways from general purpose processors. Typically these embedded systems include deadline driven constraints called real-time constraints. A particular function must be completed in a certain time or the system fails. Also, embedded systems need to minimize memory and the need to minimize power consumption. These factors are well accounted using a digital circuit designed to execute exactly one program known as Single Purpose Processor.;The main objective of this thesis is to design a single purpose, standalone, real-time, on-chip hardware processor for accessing data from a Secure Digital flash memory card using the SD bus protocol. All the hardware design is done using Verilog hardware descriptive language. This design consumes less power and is smaller in size than the comparable available technologies. It has a hardware reconfigurable feature and hence utilizes the rapid prototyping advantages.;The data access from the SD card is implemented completely using Verilog and hence there is no use of any microcontroller or on-chip general purpose processors. And since the complete design is a single purpose system, no extra hardware is required. The design has four independent modules for the required different operations on the SD memory card. These four modules are for single block write, multiple block write, single block read, and multiple block read operations. A temporary data is either stored internally in an array of registers or externally in the Synchronous RAM for the analysis purposes. The bidirectional access takes place correctly and the data integrity has been verified using Cyclic Redundancy Code in both FPGA processor as well as the SD card controller.;The design is implemented on the Altera's Cyclone II EP2C35F672C6 FPGA chip using 1GB SanDisk SD card. The data in the SD card is stored in the form of Windows wav file format. Results were verified by tracing the data on TLA611 Logic analyzer and as well as tracing the wav file on MATLAB. The closest existing comparable system takes approximately 60 seconds to write 5,000 blocks of data in the same SD card, where as each block is of 512 bytes. And as per the testing and verification results the proposed system utilizes the full bandwidth provided by the SD card technology and it can write the same 5,000 blocks of data in the SD card in 0.85 seconds. Similarly a read operation of 5,000 blocks from the same SD card is done in 1.051 seconds. The maximum data transfer rate achieved is 22.914 Mbps as compared to full bandwidth of 25 Mbps and the bandwidth utilization is 91.65%.