i2c_memutil.c

来自「* Use 10 MHz crystal frequency. * Use 」· C语言 代码 · 共 87 行

#ifndef I2CMEMUTIL_C
#define I2CMEMUTIL_C


void i2c_memwrite(char i2caddr,  unsigned int addr, unsigned char *buf);
void i2c_memread(char i2caddr,  unsigned int addr, unsigned char *buf);


#define BLKSIZE 64

//write a block
void i2c_memwrite(char i2caddr,  unsigned int addr, unsigned char *buf){

  unsigned char addr_lo, addr_hi;
  char k,ack;

  addr_lo = addr & 0x00FF;
  addr_hi = (addr >> 8);

  if (addr & 0x8000) {
    // if MSB set , set block select bit
    i2caddr = i2caddr | 0x08;
  }
  i2caddr = i2caddr & 0xFE;    //R/W# = 0;
  // check if last write complete
  do {
    i2c_start();
    ack = i2c_put_noerr(i2caddr);
    i2c_stop();
  } while(ack);  

  // now do page write
  i2c_start();
  i2c_put(i2caddr);  // send write command
  i2c_put(addr_hi); // send high address byte
  i2c_put(addr_lo); // send low address byte
  for (k=0;k<BLKSIZE;k++) {
    i2c_put(buf[k]);   // send data 
  }
  i2c_stop();
}

//read a block
void i2c_memread(char i2caddr,  unsigned int addr, unsigned char *buf){

  unsigned char addr_lo, addr_hi;
  char k,ack;

  addr_lo = addr & 0x00FF;
  addr_hi = (addr >> 8);

  if (addr & 0x8000) {
    // if MSB set , set block select bit
    i2caddr = i2caddr | 0x08;
  }
  i2caddr = i2caddr & 0xFE;    //R/W# = 0;
  // check if last write complete
  // write command will NAK if not complete
  do {
    i2c_start();
    ack = i2c_put_noerr(i2caddr);
    i2c_stop();
  } while(ack);  

  //set address counter
  i2c_start();
  i2c_put(i2caddr);  // send command
  i2c_put(addr_hi); // send high address byte
  i2c_put(addr_lo); // send low address byte
  i2caddr = i2caddr | 0x01;    //R/W# = 1;
  i2c_rstart();    // repeated start
  i2c_put(i2caddr);  // send command
  for (k=0;k<BLKSIZE;k++) {
    if (k== 63) {
      // get last byte, do NAK
      buf[k] = i2c_get(1); 
      i2c_stop(); 
    } else  
      // get data, do ACK
      buf[k] = i2c_get(0);
  }
}

#endif