Freescale Semiconductor MCF5480 - Manual (Page 679)

EU Specific Data Packet Descriptors
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 22-77
22.14.3 MDEU Mode Options and Data Packet Descriptors
The MDEU mode options, shown in Figure 22-48 , contains 8 bits which are used to program the MDEU.
The mode options are cleared when the MDEU is reset or re-initialized. Setting a reserved mode bit will
generate a data error. If the mode options are modified during processing, a context error will be generated.
Table 22-65 describes MDEU mode option fields.
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
7 6 5 4 3 2 1 0
Field CONT — INT HMAC PD ALG
Reset 0000_0000
Loc PMODE/SMODE Field in DPD Header
Figure 22-48. MDEU Mode Options
Table 22-65. MDEU Mode Option Field Descriptions
Bits Name Description
7 CONT Continue. Used during HMAC/HASH processing when the data to be hashed is spread
across multiple descriptors.
0 Don’t Continue- operate the MDEU in auto completion mode.
1 Preserve context to operate the MDEU in continuation mode.
6–5 — Reserved
4 INT Initialization. Cause an algorithm-specific initialization of the digest registers. Most
operations will require this bit to be set. Only static operations that are continuing from a
known intermediate hash value would not initialize the registers.
0 Do not initialize
1 Initialize the selected algorithm’s starting registers
3 HMAC HMAC enable. Identifies the hash operation to execute:
0 Perform standard hash
1 Perform HMAC operation. This requires a key and key length information.
Table 22-64. Typical Header Values Final Static DEU Descriptor Format (Continued)
Header Value E/C S/T E/D