DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
507 of 571
NXP Semiconductors
UM10316
Chapter 28: LPC29xx Flash/EEPROM
which is true for:
The burning is started by writing a trigger value to the FCTR register.
The page address that is offered to the flash module during burning is the page address of
the most recent data port write transfer.
Only pages within unprotected sectors can be programmed.
For burning, the flash module needs a 66 kHz CRA clock being active. This clock is
derived from the VPB clock, dividing it by a factor programmed in FCRA.FCRA. A value of
zero inactivates the CRA clock.
4.1.7 Index sector programming
The index sector is (un)protected using the same procedure as normal sector
(un)protecting (see
), except that the ISS bit is also set as FCTR trigger.
The erasable part of the index sector is erased using the same procedure as normal
sector erasing (see
), except that the ISS bit is also set as FCTR trigger.
Writable pages in the index sector are burned using the same procedure as normal
burning (see
), except that the ISS bit is also set as FCTR trigger. Data is
loaded using the normal writing and loading procedure (see
4.2 Algorithm for signature generation
To verify the flash contents, a signature can be generated by the flash module, which in
turn must be compared with an expected signature. The alternative would be reading
back all contents, which would be much more time and code consuming.
Signature generation
A signature can be generated for any part of the flash contents. The address range to be
used for signature generation is defined by writing the start address to the FMSSTART
register, and the stop address to the FMSSTOP register.
The signature generation is started by writing a ‘1’ to FMSSTOP.MISR_START. Starting
the signature generation is typically combined with defining the stop address, which is
done in another field FMSSTOP.FMSSTOP of the same register.
The time that the signature generation takes is proportional to the address range for which
the signature is generated. The asynchronous ready output RY of the memory is
synchronized and then used to trigger the reading of the next address. The wait state
register FBWST is ignored. A safe estimation for the duration of the signature generation
is:
Table 442. Burn trigger value
LOADREQ
PROGREQ
WPB
WEB
WRE
CS
burn
0
1
1
0
1
1
512
FPTR.TR
⋅
2
+
(
)
t
clk
⋅
tlw_web_write
≥
FPTR.TR
tlw_web_write
512 t
clk
⋅
------------------------------------
=