Freescale Semiconductor MCF5480 - Manual (Page 678)

MCF548x Reference Manual, Rev. 3
22-76 Freescale Semiconductor
Table 22-63 shows the final descriptor that performs a cipher on data using the key and optional context
(IV) that were loaded into the DEU by a previous descriptor, then optionally unloads the context.
Table 22-64 lists the specific descriptors that use the format shown in Table 22-63 .
0x20600010 CBC Triple DES Decrypt
0x20100010 ECB Single DES Encrypt
0x20000010 ECB Single DES Decrypt
0x20300010 ECB Triple DES Encrypt
0x20200010 ECB Triple DES Decrypt
Table 22-63. Final Descriptor for a Statically Assigned DEU
Field Name Value/Type Description
Header Table 22-64 Header common to several descriptors (TYPE 0001)
LEN_1 Length (not used) NULL
PTR_1 Pointer (not used) NULL
LEN_2 IV Length NULL
PTR_2 IV Pointer NULL
LEN_3 Key Length NULL
PTR_3 Key Pointer NULL
LEN_4 Data In Length Number of bytes of data to be ciphered (multiple of 8)
PTR_4 Data In Pointer Address of data to be ciphered
LEN_5 Data Out Length Bytes of output data (should be equal to length of data in)
PTR_5 Data Out Pointer Address to write output data
LEN_6 IV Out Length Number of bytes of output IV to be written (always 8)
(optional)
PTR_6 IV Out Pointer Address where output IV is to be written (optional)
LEN_7 MAC Out Length NULL
PTR_7 MAC Out Pointer NULL
PTR_NEXT Next Descriptor Pointer Pointer to next data packet descriptor
Table 22-64. Typical Header Values Final Static DEU Descriptor Format
Header Value E/C S/T E/D
0x20500010 CBC Single DES Encrypt
0x20400010 CBC Single DES Decrypt
0x20700010 CBC Triple DES Encrypt
Table 22-62. Typical Header Values for Middle Static DEU Descriptor Format (Continued)
Header Value E/C S/T E/D