Datasheet

 2018 Microchip Technology Inc. Data Sheet Complete DS40002060A-page 121
ATtiny4/5/9/10
1. Write the SECTION_ERASE command to the NVMCMD register
2. Start the erase operation by writing a dummy byte to the high byte of any word location inside the configuration
section
3. Wait until the NVMBSY bit has been cleared
16.4.3.5 Writing a Configuration Word
The algorithm for writing a Configuration word is as follows.
1. Write the WORD_WRITE command to the NVMCMD register
2. Write the low byte of the data to the low byte of a configuration word location
3. Write the high byte of the data to the high byte of the same configuration word location. This will start the Flash
write operation.
4. Wait until the NVMBSY bit has been cleared
16.4.4 Reading NVM Lock Bits
The Non-Volatile Memory Lock Byte can be read from the mapped location in data memory.
16.4.5 Writing NVM Lock Bits
The algorithm for writing the Lock bits is as follows.
1. Write the WORD_WRITE command to the NVMCMD register.
2. Write the lock bits value to the Non-Volatile Memory Lock Byte location. This is the low byte of the Non-Volatile
Memory Lock Word.
3. Start the NVM Lock Bit write operation by writing a dummy byte to the high byte of the NVM Lock Word location.
4. Wait until the NVMBSY bit has been cleared.
16.5 Self programming
The ATtiny4/5/9/10 don't support internal programming.
16.6 External Programming
The method for programming the Non-Volatile Memories by means of an external programmer is referred to as external
programming. External programming can be done both in-system or in mass production.
The Non-Volatile Memories can be externally programmed via the Tiny Programming Interface (TPI). For details on the
TPI, see “Programming interface” on page 104. Using the TPI, the external programmer can access the NVM control and
status registers mapped to I/O space and the NVM memory mapped to data memory space.
16.6.1 Entering External Programming Mode
The TPI must be enabled before external programming mode can be entered. The following procedure describes, how to
enter the external programming mode after the TPI has been enabled:
1. Make a request for enabling NVM programming by sending the NVM memory access key with the SKEY
instruction.
2. Poll the status of the NVMEN bit in TPISR until it has been set.
Refer to the Tiny Programming Interface description on page 104 for more detailed information of enabling the TPI and
programming the NVM.