Datasheet

SAM9G20
DS60001516A-page 128  2017 Microchip Technology Inc.
19. SAM9G20 External Bus Interface
19.1 Overview
The External Bus Interface (EBI) is designed to ensure the successful data transfer between several external devices and the embedded
Memory Controller of an Arm-based device. The Static Memory, SDRAM and ECC Controllers are all featured external Memory Controllers
on the EBI. These external Memory Controllers are capable of handling several types of external memory and peripheral devices, such
as SRAM, PROM, EPROM, EEPROM, Flash, and SDRAM.
The EBI also supports the CompactFlash and the NAND Flash protocols via integrated circuitry that greatly reduces the requirements for
external components. Furthermore, the EBI handles data transfers with up to six external devices, each assigned to six address spaces
defined by the embedded Memory Controller. Data transfers are performed through a 16-bit or 32-bit data bus, an address bus of up to
26 bits, up to eight chip select lines (NCS[7:0]) and several control pins that are generally multiplexed between the different external Mem-
ory Controllers.
19.2 Block Diagram
19.2.1 External Bus Interface
Figure 19-1 shows the organization of the External Bus Interface.