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SPI簡介

SPI ( Serial to Peripheral) 是一種通訊模式

1.同步(就是有clock)

2.Master/Slave

3.4 wired ( MOSI MISO CLK SS)

4.bi-direction (全雙工)


 

NANO130 Features

• Supports Master (max. 32 MHz) or Slave (max. 16 MHz) mode operation

• Supports 1 bit and 2 bit transfer mode

• Support Dual IO transfer mode

• Configurable bit length of a transaction from 8 to 32-bit

• Supports MSB first or LSB first transfer sequence ( 就是 Big Endian 跟 Small Endian )

• Two slave select lines supported in Master mode

• Configurable byte or word suspend mode

• Supports byte re-ordering function

• Supports variable serial clock in Master mode

• Provide separate 8-level depth transmit and receive FIFO buffer

• Supports wake-up function

• Supports PDMA transfer

• Supports three wires, no slave select signal, bi-direction interface



 

Block Diagram

 

給個Clock ，不能比APB高，Slave Mode 要比 Master高

 

Master/Slave


 


Master 可接 2 組 Slave


 

時序圖與基本測試

 

基本測試

static uint8_t spi(uint8_t data){
union{
unsigned char ch;
struct{
unsigned b0:1;
unsigned b1:1;
unsigned b2:1;
unsigned b3:1;
unsigned b4:1;
unsigned b5:1;
unsigned b6:1;
unsigned b7:1;
};
}r,d;
d.ch = data;
//---
MOSI=d.b0; SPICLK=1; r.b0=MISO; SPICLK=0;
MOSI=d.b1; SPICLK=1; r.b1=MISO; SPICLK=0;
MOSI=d.b2; SPICLK=1; r.b2=MISO; SPICLK=0;
MOSI=d.b3; SPICLK=1; r.b3=MISO; SPICLK=0;
MOSI=d.b4; SPICLK=1; r.b4=MISO; SPICLK=0;
MOSI=d.b5; SPICLK=1; r.b5=MISO; SPICLK=0;
MOSI=d.b6; SPICLK=1; r.b6=MISO; SPICLK=0;
MOSI=d.b7; SPICLK=1; r.b7=MISO; SPICLK=0;
//---
return r.v;
}

 

SS=0

虛線1.把MOSI資料準備好 > SCLK = 1

虛線2.讀取MISO > SCLK = 0

repeat…

SS=1

 

SPI 的通訊在底層比 I2C 簡單，但再往上會比較複雜

再去找個SPI裝置來兜

 

下一篇 就往上走與裝置溝通，並使用邏輯分析儀分析訊號

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