UG-498
ADuCM320 Hardware Reference Manual
Rev. C | Page 76 of 196
Signature
The signature is used to check the integrity of the flash device. The signature is calculated from the lowest 32-bit word to the second
highest 32-bit word in the selected block. The signature is a 24-bit CRC with an initial value of 0xFFFFFF and the following polynomial:
x
24
+
x
23
+
x
6
+
x
5
+
x
+ 1
The data is pushed into the CRC polynomial until the specified end address is reached. A block can be a single page or multiple pages.
The hardware assumes that the signature for a block is stored in the upper four bytes of the most significant page of a block; therefore,
these 32 bits are not included when generating the signature. While the signature is being computed for a particular flash, all other
accesses to the same flash are stalled.
Note that FEEADR0/FEEADR1 addresses are byte addresses but only pages need to be identified because the lower 11 bits are ignored by
the hardware. Also, ensure that the addresses written to FEEADR0 or FEEADR1 are both either in Flash 0 or Flash 1.
