3 mdeu mode options and data packet descriptors, Mdeu mode options and data packet descriptors -77 – Freescale Semiconductor MCF5480 User Manual

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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

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