
133
8111C–MCU Wireless–09/09
AT86RF231
11.1.6
Start of Security Operation and Status
A security operation is started within one SRAM access by appending the start command
AES_REQUEST = 1 (register 0x94, AES_CTRL_MIRROR) to the SPI sequence. Register
AES_CTRL_MIRROR is a mirrored version of register 0x83 (AES_CTRL).
The status of the security processing is indicated by register 0x82 (AES_STATUS). After 24 s
AES processing time register bit AES_DONE changes to 1 (register 0x82, AES_STATUS) indi-
11.1.7
SRAM Register Summary
The following registers are required to control the security module:
These registers are only accessible using SRAM write and read accesses, for details refer to
entering the SLEEP state.
11.1.8
AES SRAM Configuration Register
Register 0x82 (AES_STATUS):
This read-only register signals the status of the security module and operation.
Bit 7 - AES_ER
This SRAM register bit indicates an error of the AES module. An error may occur for instance
after an access to SRAM register 0x83 (AES_CTRL) while an AES operation is running or after
reading less than 128 bits from SRAM register space 0x84 - 0x93 (AES_STATE).
Table 11-2.
SRAM Security Module Address Space Overview
SRAM-Addr.
Register Name
Description
0x80 - 0x81
Reserved, not available
0x82
AES_STATUS
AES Status
0x83
AES_
CTRL
Security Module Control, AES Mode
0x84 - 0x93
AES_KEY
AES_STATE
Depends on AES_MODE setting:
AES_MODE = 1:
- Contains AES_KEY (key)
AES_MODE = 0 | 2:
- Contains AES_STATE (128-bit data block)
0x94
AES_
CTRL_MIRROR
Mirror of register 0x83 (AES_
CTRL)
0x95 - 0xFF
Reserved, not available
Bit
7
654
321
0
+0x82
AES_ER
Reserved
AES_DONE
AES_STATUS
Read/Write
R
RRRR
RR
R
Reset Value
0
000
0