AVR芯片是不是每一片都有一个号？

/*
* Example of using Offsetof() from stddef.h.
*
* This example reads the XMega chip serial number and revision.
*
* Who thought it was a good idea to put the revision letter on the
* bottom of the chip?
*/


#include  /* uint8_t et.al */
#include  /* offsetof() */
#include

/* From application note AVR1316: */
#include "avr_compiler.h" /* Compile with GCC release of WinAVR20090313 */
#include "sp_driver.h"

/* Change hex8() to match what your hardware needs to display a byte */
#define hex8(x) do{ /* display byte here */ }while(0)

int main( void )
{
  /* Read the part signature and revision: */
  hex8( MCU.DEVID0 ); hex8( MCU.DEVID1 ); hex8( MCU.DEVID2 );
  hex8( (uint8_t) (MCU.REVID+'A') );

  /* XMega serial number: */
  (void) SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM0 ) ); /* First read after reset or possibly Power Up returns zero, so read then toss this value */

  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM0 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM1 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM2 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM3 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM4 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, LOTNUM5 ) ) );

  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, WAFNUM ) )  );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, COORDX0 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, COORDX1 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, COORDY0 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, COORDY1 ) ) );

  /* Analog Calibrations: */
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, TEMPSENSE0 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, TEMPSENSE1 ) ) );

  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, ADCACAL0 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, ADCACAL1 ) ) );

  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, ADCBCAL0 ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, ADCBCAL1 ) ) );

  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, DACAOFFCAL ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, DACACAINCAL ) ) );

  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, DACBOFFCAL ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, DACBGAINCAL ) ) );

  /* Frequency Calibrations: */
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, RCOSC2M ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, RCOSC32K ) ) );
  hex8( SP_ReadCalibrationByte( offsetof( NVM_PROD_SIGNATURES_t, RCOSC32M ) ) );
}

The production signature row also contains a device ID that identify each microcontroller devicetype, and a serial number that is unique for each manufactured device. The serial number consistof the production LOT number, wafer number, and wafer coordinates for the device.