Datasheet

393
XMEGA B [DATASHEET]
8291B–AVR–01/2013
Notes: 1. If the EESAVE fuse is programmed, the EEPROM is preserved during chip erase.
2. For consistency the name Calibration Row has been renamed to Production Signature Row throughout the document.
30.12.3.1 Chip Erase
The chip erase command is used to erase the flash program memory, EEPROM and lock bits. Erasing of the EEPROM
depends on EESAVE fuse setting. Refer to “FUSEBYTE5 – Fuse Byte 5” on page 34 for details. The user signature row,
production signature (calibration) row, and fuses are not affected.
1. Load the NVM CMD register with the chip erase command.
2. Set the CMDEX bit in the NVM CTRLA register. This requires the timed CCP sequence during self-programming.
Once this operation starts, the PDI bus between the PDI controller and the NVM is disabled, and the NVMEN bit in the
PDI STATUS register is cleared until the operation is finished. Poll the NVMEN bit until this is set, indicating that the PDI
bus is enabled.
The BUSY flag in the NVM STATUS register will be set until the operation is finished.
30.12.3.2 Read NVM
The read NVM command is used to read the flash, EEPROM, fuses, and signature and production signature (calibration)
row sections.
1. Load the NVM CMD register with the read NVM command.
2. Read the selected memory address by executing a PDI read operation.
Dedicated read EEPROM, read fuse, read signature row, and read production signature (calibration) row commands are
also available for the various memory sections. The algorithm for these commands are the same as for the read NVM
command.
0x39 Boot loader section CRC NVMAA Y Y
Production Signature (Calibration)
(2)
and User Signature Sections
0x01 Read user signature row PDI read N N
0x18 Erase user signature row PDI write N Y
0x1A Write user signature row PDI write N Y
0x02 Read calibration row PDI read N N
Fuses and Lock Bits
0x07 Read fuse PDI read N N
0x4C Write fuse PDI write N Y
0x08 Write lock bits CMDEX Y Y
EEPROM Page Buffer
0x33 Load EEPROM page buffer PDI write N N
0x36 Erase EEPROM page buffer CMDEX Y Y
EEPROM
0x30 Erase EEPROM CMDEX Y Y
0x32 Erase EEPROM page PDI write N Y
0x34 Write EEPROM page PDI write N Y
0x35 Erase and write EEPROM page PDI write N Y
0x06 Read EEPROM PDI read N N
CMD[6:0] Commands / Operation Trigger
Change
Protected
NVM Busy