atxmega192a1-au ATMEL Corporation, atxmega192a1-au Datasheet - Page 13

• Manufacturer Part Number: atxmega192a1-au
• Description: 8/16-bit Xmega A1 Microcontroller
• Manufacturer: ATMEL Corporation

7.4.4
8067M–AVR–09/10
EBI - External Bus Interface
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The External Bus Interface (EBI) is the interface for connecting external peripheral and memory
to the data memory space. The XMEGA A1 has 3 ports that can be used for the EBI. It can inter-
face external SRAM, SDRAM, and/or peripherals such as LCD displays and other memory
mapped devices.
The address space, and the number of pins used, for the external memory is selectable from
256 bytes (8-bit) and up to 16M bytes (24-bit). Various multiplexing modes for address and data
lines can be selected for optimal use of pins when more or less pins is available for the EBI.
Each of the four chip selects has seperate configuration, and can be configured for SRAM,
SRAM Low Pin Count (LPC) or SDRAM. The data memory address space associated for each
chip select is decided by a configurable base address and address size for each chip celect.
For SDRAM both 4-bit SDRAM is supported, and SDRAM configurations such as CAS Latency
and Refresh rate is configurable in software.
The EBI is clocked from the Peripheral 2x Clock, running up to two times faster than the CPU
and supporting speeds of up to 64 MHz.
Supports SRAM up to
Supports SDRAM up to
Four software configurable Chip Selects
Software configurable Wait State insertion
Clocked from the Peripheral 2x Clock at up to two times the CPU clock speed
– 512K Bytes using 2-port EBI
– 16M Bytes using 3-port EBI
– 128M bit using 3-port EBI
XMEGA A1
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