ATMEGA16A_1 Datasheet, PDF (136/352 Pages) ATMEL Corporation – 8-bit Microcontroller with 16K Bytes In-System Programmable Flash

18. SPI – Serial Peripheral Interface
18.1 Features
• 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
18.2 Overview
The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer between the
ATmega16A and peripheral devices or between several AVR devices. The ATmega16A SPI
iSPI Block Diagram⁽¹⁾
DIVIDER
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Note: 1. Refer to Figure 1-1 on page 2, and Table 12-6 on page 57 for SPI pin placement.
The interconnection between Master and Slave CPUs with SPI is shown in Figure 18-1. The sys-
tem consists of two Shift Registers, and a Master clock generator. The SPI Master initiates the
communication cycle when pulling low the Slave Select SS pin of the desired Slave. Master and
136 ATmega16A
8154B–AVR–07/09