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UM10503
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
1369 of 1441
NXP Semiconductors
UM10503
Chapter 50: LPC43xx/LPC43Sxx EEPROM memory
50.6 Functional description
50.6.1 Initialization
At power-up, the reset should be applied for at least 100us. However a normal reset (not
at power-up) period is only 40 ns.
After the reset period the controller initializes the EEPROM by reading the first word
(containing trimming information) of the last (protected) page of the EEPROM. The
information that is read is used as input values of the EEPROM device and is ignored by
the controller and not visible on the APB bus.
During the EEPROM reset and initialization any started AHB/APB transfer will stall the
bus.
50.6.2 EEPROM operations
An EEPROM device cannot be programmed directly. Writing data to it and the actual
erase/program of the memory are two separate steps.
1. Write 1 word (4 bytes) to 32 words (128 bytes) to the desired page in the 16 kB
EEPROM address space. There are 128 pages in the 16 kB EEPROM address
space. Page 1 begins at the first address of the EEPROM address space
(EEPROM_START = 0x2004 0000). Page 2 begins at EEPROM 128, page
3 begins at EEPROM 256, etc. Writes to a page cannot cross a 128 page
boundary.
Remark:
Before reading this data from the EEPROM or writing to another page,
program the contents of the page register into the EEPROM.
2. Program the data into the EEPROM with the erase/program command issued via the
EEPROM CMD register on the APB.
50.6.2.1 Writing and erase/programming
Writing an EEPROM page is achieved by AHB writes.
Partial page writes are allowed, and the EEPROM will only take locations where a word
has been written for the erase/program cycle. Any word in a page can be written in any
order, but every word in the page may only be written once.
The address of the AHB transfer prior to the erase/program cycle will determine the page
address for the erase/program cycle.
The following modes are supported for the write and erase/programming operation:
•
AUTOPROG = 00: When the page has been written (fully or partially), the data has to
be programmed into non-volatile memory. The erase/program cycle is triggered by
writing 0x6 to the CMD register. The page that is programmed is determined by the
address of the last AHB transfer. Therefore it is advised to perform a page write with
the page address and to prevent AHB reads between page register writes and the
erase/program trigger.
•
AUTOPROG = 01: Writing a single word to the page starts the erase/program cycle
automatically. This mode is useful store small data items (word) on random locations.