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UM10601
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Preliminary user manual
Rev. 1.0 — 7 November 2012
235 of 313
NXP Semiconductors
UM10601
Chapter 19: LPC800 Flash controller
When signature generation is triggered via software, the duration is in AHB clock cycles,
and tcy is the time in ns for one AHB clock. The SIG_DONE bit in FMSTAT can be polled
by software to determine when signature generation is complete.
After signature generation, a 32-bit signature can be read from the FMSW0 register. The
32-bit signature reflects the corrected data read from the flash and the flash parity bits and
check bit values.
19.5.1.3 Content verification
The signature as it is read from the FMSW0 register must be equal to the reference
signature. The following pseudo-code shows the algorithm to derive the reference
signature:
sign = 0
FOR address = FMSSTART.START to FMSSTOP.STOPA
{
FOR i = 0 TO 30{
nextSign[i] = f_Q[addredd[i] XOR sign[i + 1]
nextSign[31] = f_q[address[31] XOR sign[0] XOR sign[10] XOR sign[30] XOR sign[31]
sign = nextSign
}
}
signature32 = sign