UM10375 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
User manual Rev. 3 — 14 June 2011 346 of 368
NXP Semiconductors
UM10375
Chapter 21: LPC13xx Flash memory programming firmware
If signature generation is triggered via JTAG, the duration is in JTAG tck cycles, and tcy is
the time in ns for one JTAG clock. Polling the SIG_DONE bit in FMSTAT is not possible in
this case.
After signature generation, a 128-bit signature can be read from the FMSW0 to FMSW3
registers. The 128-bit signature reflects the corrected data read from the flash. The 128-bit
signature reflects flash parity bits and check bit values.
Content verification
The signature as it is read from the FMSW0 to FMSW3 registers must be equal to the
reference signature. The algorithms to derive the reference signature is given in
Figure 65
.
Fig 65. Algorithm for generating a 128 bit signature
sign = 0
FOR address = FMSTART.FMSTART TO FMSTOP.FMSTOP
{
FOR i = 0 TO 126
nextSign[i] = f_Q[address][i] XOR sign[i+1]
nextSign[127] = f_Q[address][127] XOR sign[0] XOR sign[2] XOR
sign[27] XOR sign[29]
sign = nextSign
}
signature128 = sign
To Next Page
Loading...
Need help?
General
