ATmega1284PR231 Atmel Corporation, ATmega1284PR231 Datasheet - Page 130

• Manufacturer Part Number: ATmega1284PR231
• Manufacturer: Atmel Corporation

Specifications of ATmega1284PR231

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 20 MHz
• Max I/o Pins: 32
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Crypto Engine: AES
• Sram (kbytes): 16
• Eeprom (bytes): 4096
• Operating Voltage (vcc): 1.8 to 3.6
• Timers: 3
• Frequency Band: 2.4 GHz
• Max Data Rate (mb/s): 2
• Antenna Diversity: Yes
• External Pa Control: Yes
• Power Output (dbm): 3
• Receiver Sensitivity (dbm): -101
• Receive Current Consumption (ma): 13.2
• Transmit Current Consumption (ma): 14.4
• Link Budget (dbm): 104

Figure 11-1. ECB Programming SPI Sequence - Encryption
8111C–MCU Wireless–09/09
0 1 0 0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0
byte 0 (cmd.)
SRAM write
A security operation can be 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).
Summarizing, the following steps are required to perform a security operation using only one
SPI access:
This sequence is recommended because the security operation is configured and started within
one SPI transaction.
The ECB encryption operation is illustrated in
shows the ECB decryption mode, which is supported in a similar way.
Figure 11-2. ECB Mode - Encryption
Figure 11-3. ECB Mode - Decryption
byte 1 (address)
1. Configure SPI Access
2. Configure AES Operation
3. Write 128-bit data block
4. Start AES Operation
0x83
Decryption
Encryption
Key
Key
byte 2 (AES cmd)
ECB, encryption
Block Cipher
Encryption
Ciphertext
Block Cipher
Plaintext
Decryption
Ciphertext
Plaintext
a) SRAM Write, refer to
b) Start Address 0x83
Address 0x83: select ECB mode, direction
Addresses 0x84 - 0x93: either plain or ciphertext
Addresses 0x94: start AES operation, ECB mode
data_0[7:0]
byte 3 (data)
Figure 11-2 on page
Encryption
Decryption
Key
Key
data_15[7:0]
byte 18 (data)
Section 6.2.3
130.
Block Cipher
Encryption
Block Cipher
Ciphertext
Plaintext
Decryption
Ciphertext
Figure 11-3 on page 130
Plaintext
AT86RF231
1 0 0 0 0 0 0 0
byte 19 (AES cmd)
AES start
130