EP501

The EP501 NAND Flash controller provides an easy interface for user to access NAND Flash devices. Typical NAND Flash devices are accessed through complicated sequence of command, address, data, and confirmation protocols. The EP501 manages all the hardware protocols and allows the user to access NAND Flash memory simply by reading and writing control registers inside the EP501.

A very large size of NAND Flash memory can be accessed through a small number of control registers. The NAND Flash controller occupies only a small size in the system's memory space without scarifying system performance. Burst access to the NAND Flash memory is supported by the controller at full memory bandwidth. Timing parameters of the controller is fully programmable so different memory speeds are supported regardless of the operating frequency of the controller.

The EP501 supports optional error correction code (ECC) that performs single-bit error correction and double-bit error detection. There are options to provide ECC protection on per word basis or per page basis. With per word ECC, 8 bits of ECC code is generated by the core for each 32-bit data. A total for 40 bit is written to the NAND Flash for each data word. Error detection and correction are automatically performed by the core with error logging through internal control registers. The core can be configure to generate interrupt on ECC error. ECC error can also be injected into the NAND Flash device if desired for diagnostic purpose. With per page ECC, 3 bytes of ECC code is generated for every page (512 bytes) of data.

The EP501 is programmable to support both large block and small block NAND Flash devices. Memory size, bus width, access timing, and number of banks are all programmable.

Several options of user interface are available for the user to choose from. The standard version features a simple user interface that is designed for on-chip system integration. It has separate address and data buses and command signals that supports burst transfer and wait state insertion. Other standard interface buses including PCI, AMBA AHB, PCMCIA, and CardBus are available. The controller acts as a target or slave device on these buses. With these standard bus interfaces,the EP501 can be integrate seamlessly with systems built on these standards.