at88sa102s ATMEL Corporation, at88sa102s Datasheet - Page 11

• Manufacturer Part Number: at88sa102s
• Description: Cryptoauthentication
• Manufacturer: ATMEL Corporation

3.1.2. Transmit Flag
3.1.3. Sleep Flag
3.1.4. Pause State
8584A–SMEM–03/09
The transmit flag is used to turn around the signal so that CryptoAuthentication can send data back to the system,
depending on its current state. The bytes that CryptoAuthentication returns to the system depend on its current state as
follows:
Table 6.
CryptoAuthentication always transmits complete blocks to the system, so in the above table the status/error bytes
result in 4 bytes going to the system – count, status/error, CRC x 2.
After receipt of a command block, CryptoAuthentication will parse the command for errors, a process which takes
t
there was an error then CryptoAuthentication will respond with an error code. If there is no error then
CryptoAuthentication internally transitions automatically from t
tokens until both delays are complete.
The sleep flag is used to transition CryptoAuthentication to the low power state, which causes a complete reset of
CryptoAuthentication’s internal command engine and input/output buffer. It can be sent to CryptoAuthentication at any
time when CryptoAuthentication will accept a flag.
To achieve the specified I
To achieve I
to avoid additional leakage on the input circuit of the chip.
The system must calculate the total time required for all commands to be sent to CryptoAuthentication during a single
session, including any inter-bit/byte delays. If this total time exceeds t
of commands, then a Sleep flag, then a Wake token, and finally after the wake delay the remaining commands.
The pause state is entered via the PauseLong command and can be exited only when the watchdog timer has expired
and the chip transitions to a sleep state. When in the pause state, the chip ignores all transitions on the signal pin but
does not enter a low power consumption mode.
PARSE
After wake, but prior to first
command
After successful command
execution
Execution error
After CRC or other
communications error
State Description
(Refer to
SLEEP
Return Codes
Section
if the sleep state of the input pin is high, the voltage on the input signal should be within 0.5V of V
3.1.1). After this interval the system can send a transmit token to CryptoAuthentication – if
SLEEP
, Atmel recommends that the input signal be brought below V
Error/Status
0xFF
0x11
0x0F
–
Indication that a proper wake token has been received by
CryptoAuthentication.
Return bytes per “Output Parameters” in Command section of this
document. In some cases this is a single byte with a value of 0x00
indicating success. The transmit flag can be resent to
CryptoAuthentication repeatedly if a re-read of the output is
necessary.
Command was properly received but could not be executed by
CryptoAuthentication. Changes in CryptoAuthentication state or the
value of the command bits must happen before it is re-attempted.
Command was NOT properly received by CryptoAuthentication and
should be re-issued by the system. No attempt was made to execute
the command.
PARSE
AT88SA102S [Preliminary]
WATCHDOG
to t
EXEC
Description
then the system must issue a partial set
and will not respond to any transmit
IL
when the chip is asleep.
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