AMD 34108b geode nandflash appnote free download

File name 34108b_geode_nandflash_appnote.pdf

AMD GeodeTM Solutions External NAND Flash Memory Circuit on IDE Interface 1.0 Scope This application note describes an external NAND Flash Additional decode circuitry is required to have either a hard module and explains how to connect it to an AMD GeodeTM disk and a NAND device, or multiple NAND devices on the Solutions based system via its IDE interface. The GeodeTM same IDE channel. The decode could exist as a GPIO sig- CS5535 and CS5536 companion devices both feature nal and its complement to gate the CS0# signals to the NAND Flash controllers, however, this Flash on IDE solu- hard disk and the NAND device. Figure 2-2 shows a exam- tion yields better performance. The NAND Flash module in ple of how this could be realized. this application is used by the system for the operating sys- VCC tem. The NAND device is not used for BIOS storage. Note: This is revision B of this document. The change from revision A (dated July 2005) is the addition of the second sentence in the scope for clarification. GPIOx CS0# to IDE IDE_CS0# Hard-disk CS0# 2.0 Discussion CS0# to The NAND flash module connects to the AMD Geode NAND CE# device's IDE interface to provide higher data throughput than can be achieved using an ISA bus interface. Figure 2- Figure 2-2. Additional Decode Circuitry 1 shows a typical application that is functional in a system where the NAND device is the only device on its IDE chan- The addressing for the various ports on the NAND device nel. Two possible architectures that support this scheme are dependant upon which IDE channel the NAND device are: is connected to. Table 2-1 lists the NAND device ports and