Freescale Semiconductor MCF5480 - Manual (Page 684)

MCF548x Reference Manual, Rev. 3
22-82 Freescale Semiconductor
Table 22-74 lists several different descriptors that use the final MDEU descriptor format shown in
Table 22-73 .
22.14.4 RNG Data Packet Descriptors
There is one RNG-specific data packet descriptor. It causes a read of the RNG’s output FIFO and then
writes the specified number of random bytes into external memory.
NOTE
There RNG EU does not contain any user writable mode options, so it is not
defined here. The PMODE field in the header should always be ‘0’ for RNG
data packet descriptors.
PTR_3 Key Pointer Pointer to key (only used for HMAC mode)
LEN_4 Data In Length Number of bytes of data to be hashed
PTR_4 Data In Pointer Pointer to data to perform hash upon
LEN_5 Data Out Length NULL
PTR_5 Data Out Pointer NULL
LEN_6 IV Out Length Number of bytes of data after hashing (16, 20, or 32 bytes)
PTR_6 IV Out Pointer Pointer to location where hash output is to be written
LEN_7 MAC Out Length NULL
PTR_7 MAC Out Pointer NULL
PTR_NEXT Next Descriptor Pointer Pointer to next data packet descriptor
Table 22-74. Typical Header Values for Using Final Static MDEU Descriptor Format
Header Value Algorithm HMAC Pad
0x30500010 SHA256 No Yes
0x30600010 MD5 No Yes
0x30400010 SHA No Yes
0x30D00010 SHA256 Yes Yes
0x30E00010 MD5 Yes Yes
0x30C00010 SHA Yes Yes
Table 22-75. RNG Descriptor Format
Field Name Value/Type Description
Header 0x4000_0010 RNG descriptor (TYPE 0001)
LEN_1 Length (not used) NULL
PTR_1 Pointer (not used) NULL
Table 22-73. Final Descriptor for a Statically Assigned MDEU (Continued)
Field Name Value/Type Description