AT32UC3A4256 Atmel Corporation, AT32UC3A4256 Datasheet - Page 181

• Manufacturer Part Number: AT32UC3A4256
• Manufacturer: Atmel Corporation

Specifications of AT32UC3A4256

• Flash (kbytes): 256 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 66 MHz
• Cpu: 32-bit AVR
• Hardware Qtouch Acquisition: No
• Usb Transceiver: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device + OTG
• Spi: 6
• Twi (i2c): 2
• Uart: 4
• Ssc: 1
• Sd / Emmc: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.0 to 3.6
• Operating Voltage (vcc): 3.0 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

32072G–11/2011
•Byte write access
•Byte select access
Figure 15-5.
The byte write access mode supports one byte write signal per byte of the data bus and a single
read signal.
Note that the SMC does not allow boot in byte write access mode.
The byte write access mode is used to connect two 8-bit devices as a 16-bit memory.
The byte write option is illustrated on
In this mode, read/write operations can be enabled/disabled at a byte level. One byte select line
per byte of the data bus is provided. One NRD and one NWE signal control read and write.
• For 16-bit devices: the SMC provides NWR0 and NWR1 write signals for respectively byte0
• For 16-bit devices: the SMC provides NBS0 and NBS1 selection signals for respectively
(lower byte) and byte1 (upper byte) of a 16-bit bus. One single read signal (NRD) is provided.
byte0 (lower byte) and byte1 (upper byte) of a 16-bit bus. The byte select access is used to
connect one 16-bit device.
Memory Connection for a 16-bit Data Bus
SMC
D[15:0]
NCS[2]
A[19:2]
NBS0
NBS1
NWE
NRD
A1
Figure 15-6 on page
182.
D[15:0]
A[18:1]
A[0]
Low Byte Enable
High Byte Enable
Write Enable
Output Enable
Memory Enable
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