Rainbow Electronics ATmega128RFA1 - Manual (Page 96)

96
8266A-MCU Wireless-12/09
ATmega128RFA1
The status of the security processing is indicated by register AES_STATUS. After a
AES processing time of 24 µs the register bit AES_DONE changes to 1 (register
AES_STATUS) indicating that the security operation has finished (see
"Digital Interface
Timing Characteristics" on page 507 ).
The end of the AES processing can also be indicated by the AES_READY Interrupt.
The bit AES_ER of register AES_STATUS is set if the operation has finished with an
error. Otherwise this bit is zero but AES_DONE is ‘1’.
9.8.8.5 AES Interrupt Handling
The AES Interrupt handling is slightly different from all other IRQ’s. If the AES_IM Bit
(AES_CTRL Register) and the global interrupt enable flag is set, the AES core can
generate an AES Ready Interrupt (AES_READY). If the IRQ is issued, the
AES_STATUS register must be read to check the finish status of the last operation. If
AES_DONE is set, the last AES operation finished successfully. If AES_ER is set, an
error occurred during the last operation. The AES_ER flag is cleared automatically
during the read access to the AES_STATUS register. The AES_DONE flag is cleared
during the next read or write access to the AES_STATE (AES data) register.
The two status flags must be cleared before a new Interrupt can be issued.
If AES_IM is not set, the processing status can be polled by software (AES_STATUS
register), but no Interrupt occurs.
9.9 Continuous Transmission Test Mode
9.9.1 Overview
The 2.4GHz transceiver offers a Continuous Transmission Test Mode to support final
application / production tests as well as certification tests. In this test mode the radio
transceiver transmits continuously a previously transferred frame (PRBS mode) or a
continuous wave signal (CW mode).
In CW mode two different signal frequencies per channel can be transmitted:
• f
1
= f
CH
+ 0.5 MHz
• f
2
= f
CH
- 0.5 MHz
Here f
CH
is the channel center frequency programmed by register PHY_CC_CCA.
Note that in CW mode it is not possible to transmit a RF signal directly on the channel
center frequency. PSDU data in the Frame Buffer must contain at least a valid PHR
(see section
"Introduction – IEEE 802.15.4-2006 Frame Format" on page 61 ). It is
recommended to use a frame of maximum length (127 bytes) and arbitrary PSDU data
for the PRBS mode. The SHR and the PHR are not transmitted. The transmission starts
with the PSDU data and is repeated continuously.
9.9.2 Configuration
All register configurations shall be setup as follows before enabling Continuous
Transmission Test Mode:
• TX channel setting (optional);
• TX output power setting (optional);
• Mode selection (PRBS / CW);
An access to the registers TST_CTRL_DIGI and PART_NUM enables the Continuous
Transmission Test Mode.