Key Register
Output Buffer
(plain text)
DES Core
(encrypt)
64
Key in
192
data_out
Input Buffer
(plain text)
64
data_in
Decryption
Key Register
Output Buffer
(plain text)
DES Core
(encrypt)
64
Key in
192
data_out
Input Buffer
(plain text)
64
data_in
Encryption
Software Reset
856
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Data Encryption Standard Accelerator (DES)
14.4 Software Reset
lists the resets used in the DES module.
Table 14-2. DES Reset Description
Type
Name
Source
Description
Hardware
DES_RST
PRCM
Global reset
Software
DES_SYSCONFIG [1]
SOFTRESET
Internal
Starts the soft reset sequence. When the
DES_SYSSTATUS/DES_P_SYSSTATUS[0] RESETDONE bit
goes to 1, the soft reset sequence is finished.
14.5 DES Supported Modes of Operation
14.5.1 ECB Feedback Mode
shows the basic ECB feedback mode of operation, where the input data is passed directly to
the basic cryptographic core and the output of the cryptographic core is passed directly to the output
buffer. For decryption the DES core operates in reverse, this means the decrypt key sequence is used for
the data processing, where encryption uses the encrypt key sequence.
Figure 14-2. DES – ECB Feedback Mode