Ну не нужен мне ихний NVM котроллер.
Хочу получить обычный по байтовый доступ к епрому.
С помощью EEMAPEN можно получить доступ к епрому с адреса 0x1000 но только для чтения или для записи тоже?
Могу ли я дождавшись готовности NVMBUSY просто командой STS записать байт в еепром?

3.2 Memory-mapped Access
Memory-mapped access means that EEPROM read and page buffer load operations
are mapped into data space. This means that EEPROM data can be read simply by
reading from a location in data memory.
...
Page buffer loading is also simply a matter of writing to data memory. However,
flushing the buffer and erasing and writing pages must still be done through the NVM
controller as for I/O-mapped access. Also, the NVM controller must not be busy when
accessing EEPROM.
The necessary steps to perform an atomic write using memory-mapped access are
as follows:
1. Wait for any pervious NVM operations to finish.
2. Load page buffer by writing directly to data space, while staying inside one
EEPROM page.
3. Load the NVM Address registers (ADDRn) with an EEPROM address within the
page to be updated.
4. Issue the EEPROM Atomic Write command (byte value 0x35) to the NVM
controller.
5. The operation is finished when the NVM Busy bit is cleared.

The procedure is similar for erase and split write operations. In short, reading data
and loading the page buffer is replaced by memory-mapped access. The rest is
similar to I/O-mapped access.

ПМСМ, это вопрос раздела "для начинающих", а здесь злостный ОФФ.
На него есть прямой ответ в "писаниях".