ATXMEGA256A3B-MH Atmel, ATXMEGA256A3B-MH Datasheet - Page 275

• Manufacturer Part Number: ATXMEGA256A3B-MH
• Description: MCU AVR 256KB FLASH A3B 64-QFN
• Manufacturer: Atmel
• Series: AVR® XMEGAr

Specifications of ATXMEGA256A3B-MH

• Core Processor: AVR
• Core Size: 8/16-Bit
• Speed: 32MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Size: 256KB (128K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.6 V ~ 3.6 V
• Data Converters: A/D 16x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Processor Series: ATXMEGA256x
• Core: AVR8
• Data Bus Width: 8 bit, 16 bit
• Data Ram Size: 16 KB
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 49
• Number Of Timers: 7
• Operating Supply Voltage: 1.6 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 8 Channel
• On-chip Dac: 12 bit, 2 Channel
• For Use With: ATAVRONEKIT - KIT AVR/AVR32 DEBUGGER/PROGRMMRATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATXMEGA256A3B-MU; ATXMEGA256A3B-MU

24.8.4
24.8.5
24.8.6
24.9
8077H–AVR–12/09
Combined SRAM & SDRAM Configuration
Timing
Initialization
Refresh
Figure 24-9. 4-Port SDRAM configuration
The Clock Enable (CKE) signal is required for SDRAM when the EBI is clocked at 2x the CPU
clock speed.
Configuring Chip Select 3 to SDRAM will enable the initialization of the SDRAM. The “Load
Mode Register” command is automatically issued at the end of the initialization. For the correct
information to be loaded to the SDRAM, one must do one of the following:
1.
2.
initialized.
The SDRAM initialization is non-interruptible by other EBI accesses.
The EBI will automatically handle the refresh of the SDRAM as long as the refresh period is con-
figured. Refresh will be done as soon as available after the refresh counter reaches the period.
The EBI can collect up to 4 refresh commands in case the interface is busy on another chip
select or in the middle of a read/write at a time a refresh should have been performed.
Combined SRAM and SDRAM configuration enables the EBI to have both SDRAM and SRAM
connected at the same time. This only available for devices with 4 port EBI interface.
10 on page 276
Configure SDRAM control registers before enabling Chip Select 3 to SDRAM.
Issue a “Load Mode Register” command and perform a dummy-access after SDRAM is
EBI
shows the configuration with all interface signals.
CAS/RE
BA[1:0]
CS[3:0]
A[11:8]
A[7:0]]
D[7:0]
DQM
CKE
RAS
CLK
WE
CLK
CKE
BA[1:0]
DQM
WE
RAS
CAS
D[7:0]
A[7:0]
A[11:8]
CS
SDRAM
XMEGA A
Figure 24-
275