AT32UC3A3128 Atmel Corporation, AT32UC3A3128 Datasheet - Page 571

• Manufacturer Part Number: AT32UC3A3128
• Manufacturer: Atmel Corporation

Specifications of AT32UC3A3128

• Flash (kbytes): 128 Kbytes
• Pin Count: 144
• Max. Operating Frequency: 66 MHz
• Cpu: 32-bit AVR
• # Of Touch Channels: 32
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 110
• Ext Interrupts: 110
• Usb Transceiver: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device + OTG
• Spi: 6
• Twi (i2c): 2
• Uart: 4
• Lin: 4
• Ssc: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 16
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 128
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: sdram
• 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: 18
• Input Capture Channels: 12
• Pwm Channels: 12
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

25.6.8
25.6.8.1
25.6.8.2
25.6.8.3
32072G–11/2011
SPI Mode
Modes of Operation
Baud Rate
Data Transfer
The USART features a Serial Peripheral Interface (SPI) link compliant mode, supporting syn-
chronous, full-duplex communication, in both master and slave mode. Writing 0xE (master) or
0xF (slave) to MR.MODE will enable this mode. A SPI in master mode controls the data flow to
and from the other SPI devices, who are in slave mode. It is possible to let devices take turns
being masters (aka multi-master protocol), and one master may shift data simultaneously into
several slaves, but only one slave may respond at a time. A slave is selected when its slave
select (NSS) signal has been raised by the master. The USART can only generate one NSS sig-
nal, and it is possible to use standard I/O lines to address more than one slave.
The SPI system consists of two data lines and two control lines:
Changing SPI mode after initial configuration has to be followed by a transceiver software reset
in order to avoid unpredictable behavior.
The baud rate generator operates as described in
on page
In SPI Master Mode:
In SPI Slave Mode:
• Master Out Slave In (MOSI): This line supplies the data shifted from master to slave. In
• Master In Slave Out (MISO): This line supplies the data shifted from slave to master. In
• Serial Clock (CLK): This is controlled by the master. One period per bit transmission. In both
• Slave Select (NSS): This control line allows the master to select or deselect a slave. In
• The Clock Selection field (MR.USCLKS) must not equal 0x3 (external clock, CLK).
• The Clock Output Select bit (MR.CLKO) must be one.
• The BRGR.CD field must be at least 0x4.
• If USCLKS is one (internal divided clock, CLK_USART/DIV), the value in CD has to be even,
• CLK frequency must be at least four times lower than the system clock.
• Up to nine data bits are successively shifted out on the TXD pin at each edge. There are no
master mode this is connected to TXD, and in slave mode to RXD.
master mode this is connected to RXD, and in slave mode to TXD.
modes this is connected to CLK.
master mode this is connected to RTS, and in slave mode to CTS.
ensuring a 50:50 duty cycle. CD can be odd if USCLKS is zero (internal clock, CLK_USART).
start, parity, or stop bits, and MSB is always sent first. The SPI Clock Polarity (MR.CPOL),
and SPI Clock Phase (MR.CPHA) bits configure CLK by selecting the edges upon which bits
are shifted and sampled, resulting in four non-interoperable protocol modes see
A master/slave pair must use the same configuration, and the master must be reconfigured if
it is to communicate with slaves using different configurations. See
551, with the following requirements:
”Baud Rate in Synchronous and SPI Mode”
Figures 25-37 and
Table
25-13.
25-38.
571