ATxmega256A3BU Atmel Corporation, ATxmega256A3BU Datasheet - Page 337

• Manufacturer Part Number: ATxmega256A3BU
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3BU

• Flash (kbytes): 256 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: 47
• Ext Interrupts: 49
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 8
• Twi (i2c): 2
• Uart: 6
• 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): 16
• Eeprom (bytes): 4096
• 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

27.7.2
27.7.3
8331A–AVR–07/11
3-Port EBI Configuration
4-Port EBI Configuration
Table 27-3.
When 3 EBI ports are available, SDRAM can be connected with 3-Port EBI configuration. When
this is done only 4-bit data bus is available, and any chip select must be controlled from software
using a general purpose I/O pin (Pxn).
Figure 27-9. 3-Port SDRAM configuration
When 4 EBI ports are available, SDRAM can be connected with 3-Port or 4-Port EBI configura-
tion. When 4-Port configuration is used, 8-bit data bus is available and all four chip selects will
be available.
Figure 27-10. 4-Port SDRAM configuration
AUTO REFRESH
LOAD MODE
SELF REFRESH
Supported SDRAM commands
EBI
EBI
Refresh one row of each bank
Load Mode Register
Activate self refresh mode
CAS/RE
CAS/RE
BA[1:0]
BA[1:0]
A[11:8]
A[11:8]
A[7:0]]
A[7:0]]
D[3:0]
D[7:0]
CS[3]
DQM
DQM
CKE
RAS
CKE
RAS
CLK
CLK
Pxn
WE
WE
Atmel AVR XMEGA AU
CLK
CKE
BA[1:0]
DQM
WE
RAS
CAS
D[3:0]
A[7:0]
A[11:8]
CS
CLK
CKE
BA[1:0]
DQM
WE
RAS
CAS
D[7:0]
A[7:0]
A[11:8]
CS
SDRAM
SDRAM
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