AT32UC3L064_1 ATMEL [ATMEL Corporation], AT32UC3L064_1 Datasheet - Page 448

• Manufacturer Part Number: AT32UC3L064_1
• Description: AVR32 32-bit Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

21. Serial Peripheral Interface (SPI)
21.1
21.2
32099A–AVR32–06/09
Features
Overview
Rev. 2.1.1.1
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The Serial Peripheral Interface (SPI) circuit is a synchronous serial data link that provides com-
munication with external devices in Master or Slave mode. It also enables communication
between processors if an external processor is connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to
other SPIs. During a data transfer, one SPI system acts as the “master”' which controls the data
flow, while the other devices act as “slaves'' which have data shifted into and out by the master.
Different CPUs can take turn being masters (Multiple Master Protocol opposite to Single Master
Protocol where one CPU is always the master while all of the others are always slaves) and one
master may simultaneously shift data into multiple slaves. However, only one slave may drive its
output to write data back to the master at any given time.
A slave device is selected when the master asserts its NSS signal. If multiple slave devices
exist, the master generates a separate slave select signal for each slave (NPCS).
The SPI system consists of two data lines and two control lines:
• Master Out Slave In (MOSI): this data line supplies the output data from the master shifted
• Master In Slave Out (MISO): this data line supplies the output data from a slave to the input of
• Serial Clock (SPCK): this control line is driven by the master and regulates the flow of the
• Slave Select (NSS): this control line allows slaves to be turned on and off by hardware.
Compatible with an embedded 32-bit microcontroller
Supports communication with serial external devices
Master or Slave Serial Peripheral Bus Interface
Connection to Peripheral DMA Controller channel capabilities optimizes data transfers
into the input(s) of the slave(s).
the master. There may be no more than one slave transmitting data during any particular
transfer.
data bits. The master may transmit data at a variety of baud rates; the SPCK line cycles once
for each bit that is transmitted.
– Four chip selects with external decoder support allow communication with up to 15
– Serial memories, such as DataFlash and 3-wire EEPROMs
– Serial peripherals, such as ADCs, DACs, LCD controllers, CAN controllers and Sensors
– External co-processors
– 4 - to 16-bit programmable data length per chip select
– Programmable phase and polarity per chip select
– Programmable transfer delays between consecutive transfers and between clock and data
– Programmable delay between consecutive transfers
– Selectable mode fault detection
– One channel for the receiver, one channel for the transmitter
– Next buffer support
– Four character FIFO in reception
peripherals
per chip select
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