Rainbow Electronics ATmega128RFA1 - Manual (Page 101)

101
8266A-MCU Wireless-12/09
ATmega128RFA1
Table 9-28 AES_MODE Register Bits
Register Bits Value Description
0 AES Mode is ECB (Electronic Code Book). AES_MODE
1 AES Mode is CBC (Cipher Block Chaining).
• Bit 4 – Res - Reserved Bit
This bit is reserved for future use. The result of a read access is undefined. The register
bit must always be written with the reset value.
• Bit 3 – AES_DIR - Set AES Operation Direction
This register bit sets the AES operation direction to either encryption or decryption.
Table 9-29 AES_DIR Register Bits
Register Bits Value Description
0 AES operation is encryption. AES_DIR
1 AES operation is decryption.
• Bit 2 – AES_IM - AES Interrupt Enable
This register bit is used to enable the AES interrupt.
• Bit 1:0 – Res1:0 - Reserved Bit
These bits are reserved for future use. The result of a read access is undefined. The
register bits must always be written with the reset value.
9.12.2 AES_STATUS – AES Status Register
Bit 7 6 5 4 3 2 1 0
NA ($13D) AES_ER Res5 Res4 Res3 Res2 Res1 Res0 AES_DONE AES_STATUS
Read/Write R R R R R R R R
Initial Value 0 0 0 0 0 0 0 0
This read-only register signals the status of the security module and operation. Note
that the AES_STATUS register is cleared when entering the radio transceiver SLEEP
state.
• Bit 7 – AES_ER - AES Operation Finished with Error
This register bit indicates an error during AES module run. An error occurs if accessing
AES_CTRL while an AES operation is running or if AES_KEY or AES_STATE Memory
is not loaded completely or less than 16 Byte read from AES_STATE.
• Bit 6:1 – Res5:0 - Reserved
These bits are reserved for future use.
• Bit 0 – AES_DONE - AES Operation Finished with Success
This register bit indicates a successfully finished operation of the AES module.