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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
479 of 571
NXP Semiconductors
UM10316
Chapter 28: LPC29xx Flash/EEPROM
•
END_OF_BURN; indicates the completion of burning a page.
•
END_OF_ERASE; indicates the completion of erasing one or more sectors.
•
END_OF_MISR; indicates the completion of signature generation.
Generation of an interrupt can be enabled (INT_SET_ENABLE register) or disabled
(INT_CLR_ENABLE register) for each of these interrupt sources. The interrupt status is
always available even if the corresponding interrupt is disabled. INT_STATUS indicates
the raw, unmasked interrupt status.
Remark:
The interrupt status of an operation should be cleared via the
INT_CLR_STATUS register before starting the operation, otherwise the status might
indicate completion of a previous operation.
Remark:
Access to flash memory is blocked during asynchronous operations and results
in wait-states. Any interrupt service routine that needs to be serviced during this period
must be stored entirely outside the flash memory (e.g. in internal RAM).
Remark:
To detect the completion of an operation (e.g. erase or burn) it is also possible to
poll the interrupt status register. This register indicates the raw interrupt status, i.e. the
status is independent of whether an interrupt is enabled or not. In this case the interrupts
of the Flash Memory Controller must be disabled (default value after reset).
Polling is the easiest way to detect completion of an operation. This method is also used
in the previous examples.
2.6 Flash memory index-sector features
The flash memory has a special index sector. This is normally invisible from the address
space. By setting the FS_ISS bit in the FCTR register the index sector becomes visible at
the flash base address and replaces all regular sectors. The layout
and
burn procedure are similar to those for regular sectors.
By writing to specific locations in this sector the following features can be enabled:
•
JTAG access protection
•
Storage of customer information
Fig 121. Index sector layout
Reserved
Reserved
JTAG
access
protection
Customer info
Customer info
Sector Security
Sector Security
Reserved
Base address of
Flash Memory
PAGES 0 - 3
PAGES 4 - 5
PAGES 6 - 7