final.pde

读取avago的optical sensor的数据

#include <math.h>

#define SSNT  10  // chip selsect(slave select), active low
#define MOSI  11  // SDA(master out, slave in)
#define MISO  12  // SDO(master in, slave out)
#define SCLK  13  // SPI clock


/* -------------------------------------------------------------------------------
 * Function name: char spi_transfer(volatile char)
 * Function description: 
 * Note: The ATMega168 has a register called SPDR that, when written to, begins  
 * an SPI transaction. Once you start a transaction, you have a choice of two 
 * ways to handle it. One is to simply wait around until the transaction is over, 
 * indicated by the SPIF bit being set. The other is to set up an interrupt 
 * vector for this bit, which will result in a designated function being called 
 * when the interrupt occurs.Performing the actual transaction over the SPI bus 
 * is handled largely in hardware.
 * -------------------------------------------------------------------------------
 */
char spi_transfer(volatile char data) { 
  SPDR = data; 

  // Loop right here until the transaction is complete. the SPIF bit is the SPI 
  // Interrupt Flag. When interrupts are enabled, and the SPIE bit is set 
  // enabling SPI interrupts, this bit will set when the transaction is finished. 
  while (!(SPSR & (1<<SPIF))){}
                                                                 
  // received data appears in the SPDR register 
  return SPDR; 
}

/* -------------------------------------------------------------------------------
 * Function name: char read_register(char) 
 * Function description: reads a register
 * -------------------------------------------------------------------------------
 */
char read_register(char register_name) { 
  char in_byte; 
  
  // need to reset bit 7 to indicate a read 
  register_name &= 127; 
  
  // SS is active low 
  digitalWrite(SSNT, LOW); 
  
  // send the address of the register we want to read first 
  spi_transfer(register_name); 
  
  // send nothing, but here's when the device sends back the register's value as an 8 bit byte 
  in_byte = spi_transfer(0); 
  
  // deselect the device 
  digitalWrite(SSNT, HIGH); 
  
  return in_byte; 
} 

/* -------------------------------------------------------------------------------
 * Function name: void write_register(char, byte)
 * Function description: writes a register
 * -------------------------------------------------------------------------------
 */
void write_register(char register_name, byte data) {   
  // set bit 7 to indicate we're doing a write 
  register_name |= 128; 
  
  // SS is active low 
  digitalWrite(SSNT, LOW); 
  
  // send the address of the register we want to write 
  spi_transfer(register_name); 
  
  // send the data we're writing 
  spi_transfer(data); 
  
  digitalWrite(SSNT, HIGH); 
}

  
/* --------------------------------------------------------------------------------
 * Fun name: void setup_spi_com ()
 * Fun desc: configures common SPI pins
 * --------------------------------------------------------------------------------
 */ 
int MOTION = 9;   

void setup_spi_com(){
  pinMode(MOSI,OUTPUT);
  pinMode(MISO,INPUT);
  pinMode(SCLK,OUTPUT);
  pinMode(MOTION,INPUT);
}

/* --------------------------------------------------------------------------------
 * Fun name: void setup_spi_acc ()
 * Fun desc: start up the device, this essentially activates the device, powers 
 *           it on, enables all axes, and turn off the self test
 * --------------------------------------------------------------------------------
 */ 
void setup_spi_acc(){
  pinMode(SSNT,OUTPUT); 
  digitalWrite(SSNT,HIGH); // disable device 
  pinMode(SSNT, OUTPUT);
  
  // Set the SPCR register to 01010000; interrupt disabled, spi enabled, msb 1st, 
  // master, clk low when idle, sample on leading edge of clk, system clock/4 rate 
  SPCR = (1<<SPE)|(1<<MSTR)|(0<<CPOL)|(0<<CPHA); 

  // Write 0x5a to register 0x3a 
  write_register(0x3a, 0x5A); 

  delay(250);
}

/* --------------------------------------------------------------------------------
 * Fun name: self_test
 * Fun desc:
 * --------------------------------------------------------------------------------
 */ 
 void self_test() {
   byte crc0, crc1, crc2, crc3;
   
   write_register(0x10, 0x01);
   
   crc0 = read_register(0x0c);
   crc1 = read_register(0x0d);
   crc2 = read_register(0x0e);
   crc3 = read_register(0x0f);
   
   Serial.print(crc0, DEC);
   Serial.print(44, BYTE);
   Serial.print(crc1, DEC);
   Serial.print(44, BYTE);
   Serial.print(crc2, DEC);
   Serial.print(44, BYTE);
   Serial.print(crc3, DEC);
   Serial.print('\n', BYTE);
   
   delay(300);
 }
 
/* --------------------------------------------------------------------------------
 * Fun name: 
 * Fun desc:
 * --------------------------------------------------------------------------------
 */ 
 
   int x_val, y_val, motion, x_sum, y_sum, product_id, inverse_product_id, motionpin;
 
void setup() { 
  Serial.begin(9600); 
  
  setup_spi_com();
  setup_spi_acc(); 
} 

void loop() { 

  product_id = read_register(0x00);
  inverse_product_id = read_register(0x3f);
  inverse_product_id = ~inverse_product_id;

  if(product_id==inverse_product_id)
  {
  motionpin = digitalRead(MOTION);    
  
  if(motionpin==0){
  motion = read_register(0x02);
  y_val = read_register(0x03); 
  x_val = read_register(0x04);

  Serial.print(x_val, DEC);
  Serial.print(44, BYTE);
  Serial.print(y_val, DEC);
  Serial.print(44, BYTE);
  Serial.print('\n', BYTE);
  }
  }
  write_register(0x00, 0x0D);
  write_register(0x3f, 0xF2);
}