ATxmega128A3U Atmel Corporation, ATxmega128A3U Datasheet - Page 331

• Manufacturer Part Number: ATxmega128A3U
• Manufacturer: Atmel Corporation

Specifications of ATxmega128A3U

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 50
• Ext Interrupts: 50
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 10
• Twi (i2c): 2
• Uart: 7
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 8
• Eeprom (bytes): 2048
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 7
• Output Compare Channels: 22
• Input Capture Channels: 22
• Pwm Channels: 22
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

27. EBI - External Bus Interface
27.1
27.2
27.3
8331A–AVR–07/11
Features
Overview
Chip Select
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The External Bus Interface (EBI) is used to connect external peripherals and memory to access
it through the data memory space. When the EBI is enabled, data address space outside the
internal SRAM becomes available using dedicated EBI pins.
The EBI can interface external SRAM, SDRAM, and peripherals such as LCD displays and other
memory mapped devices.
The address space for the external memory is selectable from 256bytes (8-bit) and up to
16Mbytes (24-bit). Various multiplexing modes for address and data lines can be selected for
optimal use of pins when more or less pins are available for the EBI. The complete memory will
be mapped into one linear data address space continuing from the end of the internal SRAM,
refer to
The EBI has four chip selects with separate configuration. Each can be configured for SRAM,
SRAM Low Pin Count (LPC) or SDRAM.
The EBI is clocked from the Fast Peripheral 2x clock, running up to two times faster than the
CPU.
For SDRAM both 4-bit and 8-bit SDRAM is supported, and SDRAM configurations such as CAS
Latency and Refresh rate is configurable in software.
For more details on SRAM and SDRAM, and how these memory types are organized and work,
refer to SRAM and SDRAM specific documentation and data sheets. This section only contains
EBI specific details.
The EBI module has four Chip Select lines (CS0 to CS3) where each can be associated with
separate address ranges. The chip selects control which memory or memory mapped external
hardware that is accessed when a given memory address is issued on the EBI. Each Chip
Select has separate configuration, and can be configured for SRAM or SRAM Low Pin Count
(LPC). Chip Select 3 can also be configured for SDRAM.
The data memory address space associated for each chip select is decided by a configurable
base address and address size for each Chip Select.
Supports SRAM up to
Supports SDRAM up to
Four software configurable Chip Selects
Software configurable Wait State insertion
Can run from the 2x Peripheral Clock frequency for fast access
– 512KBytes using 2-port EBI
– 16MBytes using 3-port EBI
– 128Mbit using 3-port EBI
”Data Memory” on page 22
for details.
Atmel AVR XMEGA AU
331