Rainbow-electronics ATmega32L Manual de usuario descargar pdf (Pagina 130)

130

ATmega32(L)

2503C–AVR–10/02

Serial Peripheral

Interface – SPI

The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer

between the ATmega32 and peripheral devices or between several AVR devices. The

ATmega32 SPI includes the following 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

Figure 65. SPI Block Diagram

(1)

Note: 1. Refer to Figure 1 on page 2, and Table 25 on page 55 for SPI pin placement.

The interconnection between Master and Slave CPUs with SPI is shown in Figure 66.

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,

, line.

SPI2X

DIVIDER

/2/4/8/16/32/64/128

1 2 ... 125 126 127 128 129 130 131 132 133 134 135 ... 312 313

Sin comentarios

Rainbow-electronics ATmega32L Manual de usuario Pagina 130