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interface can also work in a multi-master configuration.It can be used for a variety of purposes, including dual wire simplex
synchronous transmission using a two-way data line, and reliable communication using CRC calibration.
The main functions of the SPI interface are as follows:
◆
Full-duplex synchronous transmission
◆
Double wire simplex synchronous transmission with or without a third two -way data line
◆
8 or 16 bit transmission frame format selection
◆
Support master mode or slave mode
◆
Support multi-master mode
◆
Fast communication between master mode and slave mode
◆
NSS can be managed by software or hardware in both master mode and slave mode: dynamic
change of master/slave operation mode
◆
Programmable clock polarity and phase
;
◆
Programmable data order, MSB before or LSB before
;
◆
Dedicated send and receive flags th at trigger interrupts
;
◆
SPI bus busy status flag
;
◆
Hardware CRC to support reliable communication:
In send mode, the CRC value can be sent as the last byte
;
In full duplex mode, CRC check is automatically carried out on the last byte received
;
◆
Main mode failures, overloads, and CRC error flags that trigger interrupts
◆
Single-byte send and receive buffers that support DMA functionality: Generates send and receive
requests
◆
Maximum interface speed: 18Mbps
5.14 Synchronous Serial Interchip Sound
(
I2S
)
I2S is a 4-pin synchronous serial interface communication protocol that can operate in master or slave mode. It can
be configured for 16-bit, 24-bit, or 32-bit transmission, as well as input or output channels, and supports audio
sampling frequencies from 8 kHz to 96 kHz. It supports four audio standards, including the Philips I2S standard, the
MSB and LSB alignment standard, and the PCM standard.
It can work in both master and slave modes in half duplex communication. When it is the master device, it provides a clock signal to
an external slave device through the interface.
The main functions of I2S interface are as follows:
◆
Half-duplex communication (only send or receive at the same time);
◆
Master or slave operation;
◆
8-bit linear programmable pre-divider for accurate audio sampling frequency (8kHz to 96kHz);
◆
The data format can be 16-bit, 24-bit, or 32-bit;
◆
Audio channel fixed packet frame is 16 bit (16 bit data frame) or 32 bit (16, 24 or 32 bit data frame);
◆
Programmable clock polarity (stable state);
◆
Overflow flag bits in send mode and overflow flag bits in master/slave receive mode;
◆
16-bit data registers are used for sending and receiving, with one register at each end of the channel;
◆
Supported I2S protocols:
◆
I2S Philips standard
◆
MSB alignment standard (left alignment)
◆
LSB alignment standard (right alignment)
◆
PCM standard (16-bit channel frames with long or short frame synchronization or 16-bit data framesextended to
32-bit channel frames)
◆
Data direction is always MSB first;
◆
Both sending and receiving have DMA capability