ATMEga64L ATMEL Corporation, ATMEga64L Datasheet - Page 161

• Manufacturer Part Number: ATMEga64L
• Description: 8-bit AVR Microcontroller with 64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL Corporation

Serial Peripheral
Interface – SPI
2490G–AVR–03/04
The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer
between the ATmega64 and peripheral devices or between several AVR devices. The
ATmega64 SPI includes the following features:
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Figure 75. SPI Block Diagram
Note:
The interconnection between Master and Slave CPUs with SPI is shown in Figure 76.
The system consists of two Shift Registers, and a Master clock generator. The SPI Mas-
ter initiates the communication cycle when pulling low the Slave Select SS pin of the
desired Slave. Master and Slave prepare the data to be sent in their respective Shift
Registers, and the Master generates the required clock pulses on the SCK line to inter-
change data. Data is always shifted from Master to Slave on the Master Out – Slave In,
MOSI, line, and from Slave to Master on the Master In – Slave Out, MISO, line. After
each data packet, the Master will synchronize the Slave by pulling high the Slave Select,
SS, line.
When configured as a Master, the SPI interface has no automatic control of the SS line.
This must be handled by user software before communication can start. When this is
Full-duplex, Three-wire Synchronous Data Transfer
Master or Slave Operation
LSB First or MSB First Data Transfer
Seven Programmable Bit Rates
End of Transmission Interrupt Flag
Write Collision Flag Protection
Wake-up from Idle Mode
Double Speed (CK/2) Master SPI Mode
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1. Refer to Figure 1 on page 2, and Table 30 on page 72 for SPI pin placement.
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