Datasheet

300
32117D–AVR-01/12
AT32UC3C
17. External Bus Interface (EBI)
Rev.: 1.7.0.2
17.1 Features
• Optimized for application memory space support
• Integrates two external memory controllers:
– Static Memory Controller (SMC)
– SDRAM Controller (SDRAMC)
• Optimized external bus:16(or 8)-bit data bus
– Up to 24-bit Address Bus, Up to 16-Mbytes Addressable
– Optimized pin multiplexing to reduce latencies on external memories
• Up to 4 Chip Selects, Configurable Assignment:
– Static Memory Controller on Chip Select 0
– SDRAM Controller or Static Memory Controller on Chip Select 1
– Static Memory Controller on Chip Select 2
– Static Memory Controller on Chip Select 3
17.2 Overview
The External Bus Interface (EBI) is designed to ensure the successful data transfer between
several external devices and the embedded memory controller of a 32-bit AVR device. The
Static Memory and SDRAM 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 handles data transfers with up to four external devices, each assigned to four address
spaces defined by the embedded memory controller. Data transfers are performed through a 16-
8)-bit data bus, an address bus of up to 24 bits, up to four chip select lines (NCS[3:0]), and sev-
eral control pins that are generally multiplexed between the different external memory
controllers.