双机SPI全双工通讯例程

只看该作者 · 2010-1-4 23:29

/******************************************
Mega64(L)
******************************************/
#ifndef __SPI__H
#define __SPI__H

#define SS PB0 //pin 10
#define SCK PB1 //pin 11
#define MOSI PB2 //pin 12
#define MISO PB3 //pin 13
#define SPI_RX_SIZE 7
#define SPI_TX_SIZE 5
#define SS_L() PORTB &=~ (1<<SS);
#define SS_H() PORTB |= (1<<SS);
#define SPI_RX 0
#define SPI_TX 1
unsigned char spi_rx_buffer[SPI_RX_SIZE];    //SPI recv buffer
unsigned char spi_rx_head;             //SPI recv handle
unsigned char spi_rx_flag;             //rx busy
unsigned char spi_tx_buffer[SPI_TX_SIZE];    //SPI command buffer
unsigned char spi_tx_head;             //spi send handle
unsigned char spi_tx_flag;             //tx busy
unsigned char spi_mode;                //spi mode
unsigned char spi_command_flag;          //1:接收到完整数据帧
/******************************************
      init
******************************************/
void spi_rx_init( void )
{
  unsigned char temp;

  temp = SPSR;
  temp = SPCR;

  DDRB &= ~((1<<MOSI)|(1<<SCK)|(1<<SS));
  SS_H();
  PORTB |= (1<<MOSI)|(1<<SCK);
  PORTB |= 1<<MISO;
  SPCR = 0xE3;                      //setup SPI
  SPSR = 0x00;                      //setup SPI
  spi_rx_head = 0;
  spi_rx_flag = 0;
  spi_mode = SPI_RX;
  spi_command_flag = 0;
}
void spi_tx_init( void )
{
  unsigned char temp;

  DDRB &= ~(1<<MISO);
  DDRB |= (1<<SS) | (1<<SCK) | (1<<MOSI); //Set MOSI, SCK AND SS as outputs
  SS_H();
  PORTB |= 1<<MISO;

  SPCR = 0x00;
  SPCR = 0xF3;
  temp = SPSR;                      //prepare for sending
  temp = SPCR;
  spi_mode = SPI_TX;
  spi_tx_head = 0;
  spi_command_flag = 0;
}
/**************************************
0x7F type xx xx xx xx 0x0D
type : 0x01 : AD转换结果
0x02 : 其他类型数据
//byte in SPDR has been sent/received
**************************************/
#pragma interrupt_handler spi_stc_isr:18
void spi_stc_isr(void)
{
unsigned char temp;

temp = SPDR;
//Uart0_Transmit(temp);
if (spi_mode == SPI_TX)          //发送模式
{
  SS_H();
spi_tx_head ++;
if (spi_tx_head < SPI_TX_SIZE)    //发送缓冲区不为空
{
delay_us(20);
SS_L();
SPDR = spi_tx_buffer[spi_tx_head]; //发送下一个字节
}
if (spi_tx_head == SPI_TX_SIZE)    //发送缓冲区为空
{
spi_tx_head = 0;
spi_rx_init();                //重新初始化成接收模式
spi_tx_flag = 0;
}
}

只看该作者 · 2010-1-4 23:29

if (spi_mode == SPI_RX)             //接收模式
{
if (temp == 0xFF) return;          //这个问题是怎么回事情呢？
  spi_rx_flag = 1;
if (spi_rx_head < SPI_RX_SIZE)       //接收缓冲区不满
{
spi_rx_buffer[spi_rx_head] = temp;    //读取一个字节
spi_rx_head ++;
}
if (spi_rx_head == SPI_RX_SIZE)       //接收缓冲区已满
{
spi_rx_head = 0;
spi_rx_flag = 0;
spi_command_flag = 1;
}
}
}
void spi_send( void )
{
  unsigned char i,temp;

  while(spi_rx_flag) {;}
  while(spi_tx_flag) {;}
  spi_tx_init();
  spi_tx_flag = 1;

  SS_H();
  SS_L();
  SPDR = spi_tx_buffer[0];
}
#endif

只看该作者 · 2010-1-6 22:59

LZ存储的资源很丰富啊，谢谢LZ了:)

只看该作者 · 2010-1-9 00:03

牛---是双机SPI的

只看该作者 · 2010-1-11 23:14

慢慢研究去

双机SPI全双工通讯例程

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