Datasheet
55.5.2.4 ICM Region Next Address Structure Member
Name: ICM_RNEXT
Property: Read/Write
Register offset is calculated as ICM_DSCR+0x00C+RID*(0x10).
Bit 31 30 29 28 27 26 25 24
NEXT[29:22]
Access
R/W R/W R/W R/W R/W R/W R/W R/W
Reset
Bit 23 22 21 20 19 18 17 16
NEXT[21:14]
Access
R/W R/W R/W R/W R/W R/W R/W R/W
Reset
Bit 15 14 13 12 11 10 9 8
NEXT[13:6]
Access
R/W R/W R/W R/W R/W R/W R/W R/W
Reset
Bit 7 6 5 4 3 2 1 0
NEXT[5:0]
Access
R/W R/W R/W R/W R/W R/W
Reset
Bits 31:2 – NEXT[29:0] Region T
ransfer Descriptor Next Address
When configured to 0, this field indicates that the current descriptor is the last descriptor of the Secondary List,
otherwise it points at a new descriptor of the Secondary List.
55.5.3 ICM Hash Area
The ICM Hash Area is a contiguous area of system memory that the controller and the processor can access. The
physical location is configured in the ICM hash area start address register. This address is a multiple of 128 bytes. If
the CDWBN bit of the context register is cleared (i.e., Write Back activated), the ICM performs a digest write
operation at the following starting location: *(ICM_HASH) + (RID<<5), where RID is the current region context
identifier. If the CDWBN bit of the context register is set (i.e., Digest Comparison activated), the ICM performs a
digest read operation at the same address.
55.5.3.1 Message Digest Example
Considering the following 512-bit message (example given in FIPS 180-2):
“61626380000000000000000000000000000000000000000000000000000000000000000000000000000000000000
000000000000000000000000000000000018”
The message is written to memory in a Little Endian (LE) system architecture.
Table 55-2. 512 bits Message Memory Mapping
Memory Address Address Offset / Byte Lane
0x3 / 31:24 0x2 / 23:16 0x1 / 15:8 0x0 / 7:0
0x000 80 63 62 61
0x004–0x038 00 00 00 00
0x03C 18 00 00 00
The digest is stored at the memory location pointed at by the ICM_HASH pointer with a Region Offset.
SAM E70/S70/V70/V71 Family
Integrity Check Monitor (ICM)
© 2019 Microchip T
echnology Inc.
Datasheet
DS60001527D-page 1753