ATEVK1105 Atmel, ATEVK1105 Datasheet - Page 334

• Manufacturer Part Number: ATEVK1105
• Description: KIT EVAL FOR AT32UC3A0
• Manufacturer: Atmel
• Series: AVR®32r
• Type: MCUr

Specifications of ATEVK1105

• Contents: Evaluation Board, Software and Documentation
• Processor To Be Evaluated: AT32UC3A0512
• Processor Series: AVR
• Data Bus Width: 32 bit
• Interface Type: USART, TWI, USB, SPI, Ethernet
• Operating Supply Voltage: 3.3 V
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: AVR UC3
• Silicon Core Number: AT32UC3A0512
• Silicon Family Name: AVR
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT32UC3A0
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

26.7.8.2
26.7.8.3
32058J–AVR32–04/11
Data Transfer
Baud Rate
In SPI Mode, the baudrate generator operates in the same way as in USART synchronous
mode:
In SPI Master Mode:
• the external clock CLK must not be selected (USCLKS … 0x3), and the bit CLKO must be set
• to obtain correct behavior of the receiver and the transmitter, the value programmed in CD of
• if the internal clock divided (CLK_USART/DIV) is selected, the value programmed in CD must
In SPI Slave Mode:
• the external clock (CLK) selection is forced regardless of the value of the USCLKS field in the
• to obtain correct behavior of the receiver and the transmitter, the external clock (CLK)
Up to 9 data bits are successively shifted out on the TXD pin at each rising or falling edge
(depending of CPOL and CPHA) of the programmed serial clock. There is no Start bit, no Parity
bit and no Stop bit.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register
(MR). The 9 bits are selected by setting the MODE 9 bit regardless of the CHRL field. The MSB
data bit is always sent first in SPI Mode (Master or Slave).
Four combinations of polarity and phase are available for data transfers. The clock polarity is
programmed with the CPOL bit in the Mode Register. The clock phase is programmed with the
CPHA bit. These two parameters determine the edges of the clock signal upon which data is
driven and sampled. Each of the two parameters has two possible states, resulting in four possi-
ble combinations that are incompatible with one another. Thus, a master/slave pair must use the
same parameter pair values to communicate. If multiple slaves are used and fixed in different
configurations, the master must reconfigure itself each time it needs to communicate with a dif-
ferent slave.
Table 26-11. SPI Bus Protocol Mode
to “1” in the Mode Register (MR), in order to generate correctly the serial clock on the CLK pin.
must be superior or equal to 4.
be even to ensure a 50:50 mark/space ratio on the CLK pin, this value can be odd if the
internal clock is selected (CLK_USART).
Mode Register (MR). Likewise, the value written in BRGR has no effect, because the clock is
provided directly by the signal on the USART CLK pin.
frequency must be at least 4 times lower than the system clock.
See Section “26.7.1.4” on page 307.
SPI Bus Protocol Mode
0
1
2
3
However, there are some restrictions:
CPOL
0
0
1
1
AT32UC3A
CPHA
1
0
1
0
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