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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
478 of 571
NXP Semiconductors
UM10316
Chapter 28: LPC29xx Flash/EEPROM
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Protect sectors (optional).
Remark:
During the burn process the internal clock of the flash module must be enabled.
Remark:
Only erased flash-word locations can be written to.
Remark:
A complete page should be burned at one time. Before burning it again the
corresponding sector should be erased.
2.4 Flash signature generation
The flash module contains a built-in signature generator. This generator can produce a
128-bit signature (MISR) from a range of the flash memory. A typical usage is to verify the
flashed contents against a calculated signature (e.g. during programming).
Remark:
The address range for generating a signature must be aligned on flash-word
boundaries.
Remark:
Like erasing a sector or burning a page, the generation of a signature is also an
asynchronous action; i.e. after starting generation the module begins calculating the
signature, and during this process any access to the flash results in wait-states (see
). To serve interrupts or perform other actions this critical code must be
present outside flash memory (e.g. internal RAM). The code that initiates the signature
generation must also be present outside flash memory.
2.5 Flash interrupts
Burn, erase and signature generation (MISR) are asynchronous operations; i.e. after
initiating them it takes some time before they complete. During this period access to the
flash memory results in wait-states.
Completion of these operations is checked via the interrupt status register (INT_STATUS).
This can be done either by polling the corresponding interrupt status or by enabling the
generation of an interrupt via the interrupt enable register (INT_SET_ENABLE).
The following interrupt sources are available (see
Fig 120. Flash-memory burn sequence
Unprotect sectors
Enable flash clock
for each page to
be programmed
Write data to page
Start burning page
Wait for burning
to finish
Disable flash clock